I have a local friend who owns a cabinetry building business. He makes tanks for our local club members from time to time. He made this one for me when I was retailing. I used it primarily to photograph corals top-down. It has a black bottom. It was intended to be mobile to take to frag swaps, etc.
eHey Bill that's a perfect example ^above^ by benny z and AIO's (All in One) tanks can be of most any dimension. The mechanical area can be well hidden by cabinetry if desired as well. If you were closer I could/would help you build one in a weekend.