Too many variables to even guess. Mike and I build our own stands from cedar fencing and 4x4s, because we didn't like how the mass market stands were built (his tank was a 300 gal, mine was a 180). I've seen stands built by other members, and they're stunning. I just didn't ask how much they cost, because I didn't want to be nosy.
If you don't get responses in this thread, I'd post up a thread specifically asking for quotes on building a stand and canopy. The more info you can provide, the better. What kind of wood, how many doors, what style you like, etc. If you have pics of ones you like/don't like, that helps, too. You might even find someone that can build a canopy that will pair nicely with the stand that Mav has. I've seen it, and it's amazing.