Duh. I didn't even think of my Hincapie LS base layer as something that could be worn alone. The white one I definitely would not. It's super lightweight (which is why the white one is completely see-through even when it's dry), runs small and comes in XS. My Small one was skin tight before I lost all my upper body muscle.
http://www.hincapie.com/products/wom...es/RBL-LSWW09/