Can you spray Tamiya smoke?...

Yep, it can be sprayed. I thin it like my other Tamiya paints...1:1 with denatured alcohol. I've tried this to tint the exhaust cans of an aircraft model once, and the results were incredible. It cured to a nice semi-gloss sheen.

I use smoke as the base for 99% of my weathering on a/c.

I tried pre shading panel lines like most people, but it never looked 'right' to me, then I tried post shading with Tamiya smoke through the airbrush and have never looked back since.

One thing to remember when using smoke for weatehring, it should be applied BEFORE you put on your flat coat, and when properly thinned it gives excellent results, and being a light tinted colour, you can apply the right amount of weathering/staining every single time.

AB it for exhaust marks, do 2-4 applications..

I have sprayed it, and got good results. It worked great to tint headlight lenses. Somebody makes an aresol smoke (modelmaster? made by testors?) I think Tamiya even offers there smoke in a rattle can.

You sure can and the results are pretty nice. Just make sure you get the right thinning ratio. It took me a couple of sprays to find just the right mix. I use about 55-45 thinner to paint. Use Tamiya thinner

Thin a bit and spray? I've only used smoke as a brushed on weathering technique, but I can't see any reason not to load up the trusty AB and shoot. Be careful though, you wouldn't want to be left holding a smoking gun!

Sorry about that last bit. I couldn't resist.