Patagonia used to make a capilene one piece, they do not anymore. I beleive you can find one, made for cold water paddling, but I can not remember who makes it. Try the NRS website.
Paddling gear would be a good place to look, also, OR makes a one piece base layer for women called the "Banff," I don't know if they make one for men, but if they do that's your ticket right there.