Truck bed canvas covers

Probably the most common way is tissue wet down with a whiteglue/water mix (thin) and put over the bows.  You can wrinkle the tissue up fairly well before to soften it up then shape and drape/sag as you want.  Paint and weather when dry.  I would lightly wipe the bows with vaseline just to keep it from sticking as hard.

Practice over some sprue trees from the kit.

Great suggestion Goldhammer.  I did a similar thing with a 1/25 Kenworth T1200 chassis several years ago when I was detailing the cab.  I created a blanket and pillow for the bunk of the cab doing a similar technique.

I second the Kleenex and white glue method.  Most of my modeling friends use it too.  

One friend found a paint that has a canvas-like texture when it dries, but one still has to carve the canvas with a few wrinkles to make it look proper, and I don't recall the name of paint.

Thanks for the info everyone. A little out of my comfort zone, but I've got some old stuff I can practice on.

Don't use Kleenex facial tissue. Use tissue like is used in gift bags or boxes...

I didnt have any problem using kleenex facial tissue, it actually looked more like blankets and linens than gift box tissue.  I would recommend that if you use facial tissue that you make sure that it doesnt have lotion or aloe added to it.

A friend of mind builds balsa airplanes and has a bunch of tissue for covering. Would that work for replicating canvas?  Years of engineering tells me to try each of your responses and see what happens. Gives me a welcome break from the tiny little pieces.

I also have never had any problems with Kleenex or copycat stuff.  One must be careful not to tear it when it is wet, but many things we do in modeling require care.  It must be supported rather than freestanding, but this is true for covers on full size vehicles anyway.

 This time of year the gift tissue can be had from most any wally world, etc., for around a buck.  One small package will last forever.  Also look at paper towels for the different textures out there.  "Rags in a Box" has a nice texture, but might be a little big for canvas in 1/35.  About 12.00 a box at most auto parts stores.  If they don't work for modeling you can always use them for oil rags or cleaning glass.