Definately overkill...and not needed...just a waste of money.
If you're going for a tank that size, find the largest tank you can fit into the stand and use that for your sump. You could get away with a 125 - 150gal tank, install baffles...you're set. It's better and will most likely be cheaper than the wet/dry's, which are junk, IMO/IME.
Four 1100gph pumps will create so much circulation, it'll be too much. Shrink that down to a large return pump (something like a Sequence or Dolphin- 3000gph) and then maybe another pump for a closed loop, if you want to keep your tank powerhead clean.
Redundancy, in heaters, is not a bad idea. I can heat my 200gal. tank with a single 300W heater, so maybe find two 500W heaters and you're set.
You're going to want a skimmer that's gonna be rated for double your tank size...something along the lines of a unit that'll handle a 2000gal tank...NOT gonna be cheap. Look at -- and check out building your own skimmer.
I still would not, however, go with a 48" tall tank. Even if you dont have the room to 48" wide, I'd go 30" - 32" tall, at the most.