I don't know if this is helpfull or not, but when I was at a store to buy pingpongballs for eyes (sad I know, I can't find decent supplies around here, I bought a placemate to try and cut a mouthpiece out of. *sigh*)
I found the foamy rubbery golfballs. Now, there really bright, but I guess you can paint them with acrylic paint. They're solid and I haven't tried it yet, but I think you can cut them into the right shape so you can glue them on.