I was tossing around the idea as a possible spring time project.. i had planned on using just a normal plastic paint and then a clear coat to make it more durable. if it is prepped well ( denatured alcohol then right before the paint flies use a tac cloth ) the paint should stick perfectly fine... good luck and post pics if you do end up doing it.
The whole inside of my tub was destroyed because someone put tar in it and then painted over it, so it was spots of black paint that wouldn't come off & tar. Not sure why they did it, but getting it off pretty much ruined it. I painted my tub red using Krylon from Walmart. I also painted a floorpan i had welded in, and touched up a ton of spots on the outside where someone tried using that brush on paint, worked pretty good & the color matches pretty well. Painting is all about prep!