Heating isn't really a problem and WON'T be done with 16000 watts of anything. The ambient room temperature will keep the tank stable because the room is well insulated and the heat from the pumps will help as well. I'm most likely going to have more trouble keeping it cool than warm since it's hot here most of the time.
Larger tanks are actually easier to maintain than smaller tanks because there's more margin for error. As I've said, there will be a variety of smaller subsystems rather than one or two larger ones. That in itself will be easier to maintain.
Bob, I don't have a storage problem. I have a stuff stuck in boxes problem.
That and I'm a packrat don't work well together. I'm trying to get rid of everything that doesn't have a place, but when you're raised to never throw anything away it's difficult to do that.
krytan, the first stocking will be various cichlids, clown loaches, gobies, and other fish that I have right now. Once I have it working for a while, don't know how long, I'm going to stock it with arowanas and freshwater rays.