I have a bra made by Victoria Secret called the "Shock Absorber". It's a single layer of fabric, which makes a lot of difference in the evaporation rate. Because it is a single layer, it's a non-stretch fabric with lots of seams going every which way. The seams are all nicely taped, and I haven't had any issues with them. Now, the fact that it's a non-stretch fabric means they had to put in adjustable straps and back hooks. I know you're looking for something w/o adjustable straps or hooks, but everything I've worn built like that has been made of lycra-containing fabrics which just can't offer support when used in a single layer. Thus they are double layer and prone to getting all clammy, icky...well, you know. The bra of which I speak is a racer back, with the hooks in the back and getting into it can take some thought, but when I'm ready to shuck it, I just undo the hooks and, erm, pop right out, so to speak.

Aside: I'd love to stick cute smilies in here in appropriate places, but this computer won't let me! (Red-faced smiley here) So, please, ladies, insert them in your minds.