I was looking for sprayable body paint too. Found 2 suppliers, one based in the U.S., the other in China. As of June 2010, I have NOT used any product from either of these companies, so this is NOT a recommendation, just a pointer to possible suppliers.
Notes from their website:
Body Paint is just water based makeup already in liquid form.
Preferred method of application is Airbrush, Sponge, Brush in that order.
Artists who have many people to paint in a short period of time will often use a conventional paint gun (automotive style).
It takes about 16 fluid ounces to paint an average person from head to toe, one fluid ounce for an arm and hand, and two fluid ounces for a head (face and head).
Nileveggie, if you do try either of these companies, or if you find another supplier or solution, please post your experience here! (Did it work? Was it easy to use? Was it non-irritating? Did it clean up easily? Overall, were you happy with the results?) Thank you!