I'm also in the market for a small cube, a little smaller than what you want... 30ish gallons or so. I'm thinking 20 x 20 x 18. Miracles quotes me $700 including shipping. Thats with starphire glass on 3 sides. Is that a good price? I've never looked into custom tanks before... it strikes me as being a little steep. Especially if glass cages is selling a 60 gallon with stand for only $600, delivery included also. Are miracles that much better?
I don't mean to hijack, this information would probably be helpful to the OP as well