An amazing talent (and book cover illustrator) named Bruce Jensen has posted Outer Space Men custom head drawings so good, you'd swear they were real plastic. Or at least, I would. A post on his own blog highlights his latest entry, a modified crescent-inspired cyclops for the Xodiac body plus three other really nifty original designs for use on the painted bodies.
At this time there are no known plans to produce these, as they are not real three-dimensional things. You might also want to check out his alien paintings and other stuff, unrelated to the brand, but cool stuff all the same.
Hey Bruce: if you're reading I'd buy some figures. Just saying that if you put up a massive investment of tens of thousands of dollars to make these happen, I WILL buy a set. That's literally tens of dollars, right in your pocket.