I tried that donor plastic method and it didn't work very well. I even stripped the paint first. I've also tried fiberglass (a little better, but still didn't last a long time). I even tried "plastic welding" to refuse the pieces back together (even using a piece of donor lexan as filler)... let me say it wasn't pretty!
My paintjobs are really crappy as it is, so I don't think I'll paint the next body I get. I just can't justify spending so much time on something that lasts so little.
Too bad there wasn't an option to buy bodies that are made from colored lexan. Then, just add window stickers. Good for racing or bashing, and leave the really pretty ones for the shelf and forum pictures.