Yeah, that might be the biggest indoor on here I think. It's a good read.
My friend Pat has an 18,000 gallon indoor tank. I helped set it up. And as opposed to the above tank, it's an actual free standing fish tank. Not a viewable basement pond. There's a long thread floating around here about it. I'll see if I can find it.
edit/ found it. There's a bunch of pics of us plumbing it and what not in there somewhere.