I'm sorry to hear about that. That really sucks, but I do understand, that's expensive having to buy the paint all the time. It's a shame that I never got to see the costume in person, though.

Among the options you're looking into, have you though of a skin suit? It may work. It's a full-body suit, covering the feet, legs, hands, arms... everything. It's one idea, anyway. Though you'd probably want to remove the head, or at least cut out the face, and use body paint on that area instead. But even so, that would save quite a bit of paint.
Here's what I'm talking about. There's different colors, including white which could probably be dyed.
http://www.spirithalloween.com/product/light-blue-skin-suit-adult-costume1/There's a Halloween store in Beaverton that's open year-round, and just last weekend I saw some of these for sale there, if you want to look at them first. I don't remember what colors they had, but I'm sure they could special order them.