makes a lot of odd sizes or can make anything you want.
I've wanted to make a wide and long but shallow tank for a while and have been thinking of just making it from 1/4" acrylic from Home Depot. You use Weldon, a glue that actually fuses the parts together and makes them one. Takes a little practice, but it would be neat to say you made it yourself. And a small nano tank would be a nice low-risk first attempt.