G'day Mate, cool rod!! I've done a few grafix/effects on bikes(fullsize) using a process called Acrylistration.(Not sure on exact spelling). Basically, print what you want onto selected paper, photo paper comes up glossy, normal paper comes up matt, then spray several coats of acrylic clear coat, up to 10 for larger, 15 x 15cm & bigger, prints to make them more robust, but smaller pieces, or maybe people who are a bit more patient & gentle than me, can use less coats.
Leave to cure untill cured well enough to handle, anywhere from hours, to a day for thicker coats, then soak in water and GENTLY rub the paper from the back, untill you are left with just clear & ink.
To apply, simply spray the back of it and where it will sit with clear, press it on expelling all (if any) air, and then overcoat with clear to ensure solvent "regooeys" the whole thing. Bigger decals can come out reasonably thick, but as the print is at the back, you can sand it back almost to nothing. Gloss level will depend on paint used & final polishing.
Thinner pieces can be formed around parts while in the "gooey" stage of application.
Due to the thickness and poor attribites of acrylic, it hates UV, so after 5 or more years in the sun it will craze a bit, but I'd doubt that many of your models will spend everyday out in the carpark!
I've used it for difficult to reproduce effects, and as a cheaper alternative to buying different body art. Hope this helps. Sean.