hey anthony, I was looking at doing the same thing. I went to glass cages site and there premaid acrylics are really cheap. I thought about having them custom make me a 48"Lx12"x8"H. I thought would be perfect for anything, shallow enough for stonies to get good light and long enough to setup two different lights for different corals on each end. then drill it and run it off a sump. anyway, check out there site and look at there list of premaid designs. 20 gallon sizes are only like $50 - $75 and they could bring it to the frag swap, another idea is that class cages is donating 2-3 of the acrylic frag tanks between 25 and 50 gallons, you might wait and see if you can win one of those in the raffles.
I may have a cheap setup if you dont mind a 20 tall. I still have my first reef tank, it has a penguin back filter(biowheel). it has a full plastic canopy with a floresent tube. I let someone borrow the power compact light I had for it and they dropped it in there tank and never replaced it, so you would need a better bulb. let me know if your interested.