KarenM,
If you are interested, I have a 135 reef-ready I need to move, so I can set up the 200 we want to move to. Its 50"Lx24"Dx 24-25"H. Its acrylic, would come with the stand, canopy, sump, pump, 2 metal hilides, 2 VHO actinics, and either a Trigger or Aerofoamer clone skimmer (your choice). I might could throw in a Hydor or two, depending, It was originally set up for closed loop, but was not planning on selling it that way (but would if someone was interested). However, it would raise the price, because that would mean including a Dart and Sequence pump, and a lot of flexible PVC piping. The tank started leaking, and can be repaired according to Brian at Kingfish, but I would be basically giving away the tank to whoever bought the rest of the system. Brian said he could get a glass tank for it (if someone wanted to replace the acrylic one) for around $300-$350.
I could even throw in a 4" Hippo tank that is currently living in my frag tank.
I have two 90gs, and have a Hippo (bigger) in one, plus others. Per Gabriel's comment about them being too big for a 90, I have had the larger "Dori" for over a year, and had always planned on finding her another home if she got too big. So far, she seems fine.
I agree with the other comments. It seems the size doesn't make much difference in maintenance. Its about the same for a 50, 90, 135, etc. No matter what the size, you still have all the functions you have to perform. I'm sure a 300-500 would be a different story, however.
PM me if you are interested in the system, and we'll see what we coould work out.
Stephen