theres a company that makes paint meant to be peeled or washed off after a couple days or even weeks (i forget who... ill look more into it later) but i saw it on TRUCKS! on spike, you could get stuff like that and try it out, see how you like it... now that im thinking about it... i may do that with a few ideas ive had... haha

**edit**
found it! duplicolor car art

http://www.northernautoparts.com/Pro...ProductId=2595