Thanks for all of the excellent comments. I finally broke down over the weekend, and bought a pair of cycling shorts. To be specific, I stopped by Sports Authority a bought a pair of Canari Velo II shorts. They're nothing fancy, I'm sure. They were just the cheapest pair I could find at $29.99.

I wore them under a pair of ripstop cotton cargo shorts for a ten mile ride yesterday morning, and could tell after the first 1/4 mile that all of my problems were solved. It was an unbelievably comfortable ride, even under 85 degree heat and 52% humidity. I didn't want to take them off when I got home. My daughter was running under the sprinkler to stay cool, so I just took off the cargo shorts and used the Canari's as a bathing suit and joined her. They're awesome.

My wife also likes the way I look in them.