I would tend to say the hobby is probably 70/30 in favor of military stuff. 

As to colors available, those have been the standards for decades, and for some reason they don't  expand on them.  Could be the thought of return on investment for new colors, etc.

You can always get Dupli-Color etc at auto parts chains, various rattle can brands elsewhere and de-cant for AB use.  Most of those are laquer or enamel paints.

I realize not the answer you were looking for, but perhaps a work-around.

I believe that the options car modelers have is the reason. From real automotive paint, to spray paint at the local big box to even nail polish, there have been a variety of options that military modelers just don't have. You won't find dunkelgrun or Soviet cockpit green at Walmart, but there's tons that car guys can and do use. It's hard to carry a line with that much competition.

   Very nteresting observation Bluenote, I wonder if it may have to do with the idea of most car models are of vehicles produced when auto paint selection was limited. I was told that a person could buy a model T in any color they wanted...as long as it was black.

    Auto manufactures have to produce color combinations that appeal to the vast majority of consumers, similarly model car manufactures, and paint, try to produce a product that will sell. Being an armor/ aircraft guy myself it can be just as frustrating finding the right "panzer yellow", or "aircraft gray".

    The new color pallet for more modern cars is huge compared to the 50's and 60', however avid car modelers, like gearheads, modify, repaint, upgrade thier cars to thier satifaction. For example your hope for "Candy Apple Green Mettalic" in a bottle ready to airbrush may not be cost effective for Testors or other paint manufatures to produce.

      I did once speak with a PPG auto paint distributer who told me they can and occasionally do mix special colors for modelers at a reasonable cost and amount as to not have alot of waste.

     Again very interesting observation, hope I too have given you and option.

Well, don't Vallejo and AK Interactive mostly make matte acrylic paints? I've talked to a few car guys and they seem to prefer laquer and enamel paints.

I for a palette cleanser have been trying to build a car for a change and the gloss paint is driving me insane. I found these GaiaNotes paints from Sprue Brothers and ordered a few. We'll see how it goes. 

http://tatsuhobby.com/webstore/index.php?main_page=index&cPath=67_68

I will readily admit that I am a military modeler who simply does not build civilian autos at all. There were far too many incidents involving glossy enamels which never dried or cured properly back in elementary school (late 70s) that put me off the genre completely. But, most of my modelling buddies are very deeply into building cars, trucks, and motorcycles. Their big advantage when it comes to paint is that they are not limited to the paints which come from the hobby shop. Many of them simply go to the automotive supply store and pick up small bottles of touch-up paint or spray cans filled with paints matched to manufacturer specs. 

The lacquer they use is easily thinned and sprayed through an airbrush. In addition, it allows them to polish up the paint using the same products as full scale cars. I have never done it, but I strongly suspect that Vallejo would not stand up well to polishing with Micro Mesh or a rub down with polishing compound like those guys do with their models. Then again, it seems to me that using Game Color to get that coveted "competition gloss" is altogether improbable, but I'm a military guy who considers gloss as just a step for decals, so I'm speaking out of turn.

I rather envy the car modelers to some extent. The guys I have beers with use the same materials and techniques on their models and their full-scale, real world cars. That's a fascinating idea to those of us who don't have hyper detailed references like a Chiltons repair guide, factory matched paint, swirl removers, polishing compounds, wax, and so forth.

Military modelers are primarily limited to what we find in hobby specific outlets. We can't really stroll into the local AutoZone or NAPA and pick up references on German Maybach engines or ask for a paint that would match the ivory interior of a '43 Panther A with a straight face.

Most of the car modelers I know of do not build factory stocks, where you can identify specific colors.  Most of them build customs, rods, etc, and they do not stick to any restriction on color schemes.  Some of them even mix their own colors to get the effects they want.  There are a couple of mail order paint firms that do cater to factory stock and racing car colors, but I think the market for that is too small to interest major paint suppliers.

Hi ;

 I was for years specifically a car and ship modeler . The cars were always primed with Rust-Oleum primer , wet sanded and then shot with any color I chose , from Stippled Effect machinery paint to Nail Polish .

 The hobby manufactures catering to model builders have to make a market choice based on research .That says Planes , Ships and Armor come first . Even ships lag a little .For instance Japanese Ships from the war vary in color depending on which yard they were bult or repaired in !

 I have found the same to be true for Soviet Era ships . I have two Admiral Veliky class ships . Based on the colors they wore while transiting the Panama Canal they showed up two different shade of grey . One light grey and the other light grey green in the photos. !

 No one makes the different colors so I have to mix them myself . You really cannot use " Desert Sand " on a model and touch it up with another company's colors . Vallejo's " Desert Pink " doesn't come close even though it looks sand color .

 Model Car buffs do have this edge . We can paint whatever suits our fancy .You don't paint a M-1-A-1 in gloss colors . You have to stick with the Theater of Operations . We don't  . Not necessarily a good thing . Did you know for instance . That over the years Chevrolet has changed the code for one shade of white five times ?

     When you see a very Light Gold Chevy in real life . It may be called " Summer Champagne "or some such silly name . So  "Mist Gold " would not be the color you use.

 Same issue different model type .

Actual car companies limit their car colors.

Silver ;

 You are so right there .I think they have used the same pallette for fifty years that I know of . Ford for instance has good old Wimbledon White . It was for years on their trucks especially . Three name changes and it's back ! 

 Chevy did that too .1958 the white on the tops of Impalas and Biscaynes was Frost White Another name Polar white !

 Chrysler had  "Turbine Bronze" metallic in three distinct shades depending where in the country you bought it .

 The nice thing about car modeling is this . I can paint my cars factory stock colors or paint my color of choice . I did this twice . Disassembling a perfectly good New car so I could have it in the color I wanted .

 We had two home built rotisseries is in my shop , for detailing and rebuilding customers special jobs so I used one for two weeks .

 I had a Brand New Buick Riv in 68 . I didn't like the factory color after living with it for a month , So I changed it . Instead if metallic brown ( Root Beer ) as Buick called it . I painted it a beautiful and gorgeous Black/Brown metallic to show off her sexy curves .

I discovered that using "hot" urethane automotive paints is not a big deal. (Remember to add the hardener though... Ugh.) All I use to protect the styrene is a couple primer coats of Tamiya Fine. 

The paint I'm using for this is "Galaxy Blue", a 3 stage pearl. The pearl is blue, so the paint looks white while highlights are ringed in blue. Pretty neat. 

My pic isn't nearly as good. And I'm having to re-do it because I forgot the hardener. The paint will eventually harden without it, but something touched the top of the bug and left a mark in the clear. Grrr...

My pic isn't as good as the manufacturer's...