I loathe the crappy stuff from the big box pet stores, too. FWIW, I found a really great little sofa table on Overstock a few years ago that has worked out perfectly! Watch Craigslist or check thrift stores, too... some of my best "tank stands" are older, solidly-built pieces of furniture that someone rejected because they were kind of antiquated. With a nice coat of primer and paint, they're pretty darned cool now!
I'm brainstorming what sorts of surfaces I could use as a stand for a 20 long tank. I'm not seeing any existing stands that I really like in that size. I weigh almost as much as a filled 20g. tank, so I'm assuming anything that could support my weight would be doable...perhaps avoiding particle board or other surfaces that could become greatly compromised if wet.
Any BTDTs or advice?