I got the same problem. You hit it right on the head with the comment about gay-ass little shorts. If I wear a normal pair (which I do), then it looks like I've never done a set of squats in my life.
It is possible to improve lower quad thickness, but only to a point. Expecting to look like Tom Platz would probably not be a realistic goal, just like somebody with a Larry Scott bicep could never expect to have a Schwarzennegger peak, no matter how many concentration curls they did. Good luck to ya, though. I'm still working on mine.