Plastic dealies...?

[eaterofsouls.livejournal.com]

A friend of mine wants me to make him an Invader Zim themed hat, when he's in alien form. But instead of easy felt eyes, he INSISTS on having the eyes be 3-d hard plastic.

Now where in the world would I find something like that??

They'll need to be like an egg cut down the verticle axis, instead of the horizontal (so easter eggs are out of the question). Sculpey would probably be too heavy and break too easily, right?

Then I'll need some way of attaching them... any suggestions on what to do for this?