Try mountain bike shorts. AKA Baggies.

My experience has been that you get what you pay for when it comes to cycling apparel. You can cheap out if you're only doing a few miles but that's just in the comfort department. What about style? Don't ever forget style, especially if you're riding fixed.

Wait, you said small hem opening. Well then, the world of roadie cycling spandex is your oyster. Bib shorts. Once you get bibs, you won't wear anything else.