Was thinking about picking up a 20L to replace the patched swiss cheesy 30g acrylic tank I have.. the cheap ass aspect of me won over though and what I have still holds water let it go... I might change my mind, but I'm going to have to "disassemble" quite a few tanks this weekend for the garbage if I do. Also those 40B's look sexy as can be... think that might be overkill considering they're going under the stand, and might be overkill for a simply QT tank.
I remember a few years back finding the sizes you want was fairly hard, but I saw a bunch at the Tanforan Petco today, so those who live in the area there are some there.