I have built about 5 stands, as well as about 4 canopy's for my self and some of my friends. I can pretty much build what ever dimensions you want, for a 150 it would probably be doubled 2x4's for the structure, then cover it in some sort of laminated plywood and trim board, then stain it whatever color you want. Doors I have found are best made with plywood and then using baseboard around the edge to give it that polished look. You can send me a PM if you are interested, just off the top of my head id probably charge 400 including what it costs for supplies. I live in fort collins, and have the next week off for spring break so if you want it fast I can do that.
Good luck with your new tank.
-Garrett