Interesting. I was designing my next home with my tank(s) and experience in mind.
First I would design the tank so it sits somewhat in a well with a drain. this allows you to drain stuff right out the bottom of your stand, and if, god forbid, the tank gets a major leak it will go down the drain instead of flowing throughout the house... I have a little experience in that department. Caused about $15000 dollars in damage... Thank god for State Farm Insurance, I think my wife already had a divorce lawyer on retainer...
some of the other obivious things are electrical, and water under the cabinet.
My plan was for two 1000 gallon tanks framing the living room. I was going to have a seperate "pump" room to house another 1000 gallons for the refugium, frag tanks, filtration, skimming, etc. All my electrical would be controlled from the room, RO water, filtration, etc. The lighting was going to be encased from the ceiling to the top of the tanks. Air circulation would be drawn from the outdoors and vented outdoors, with temperture controlled fans. We do not have basements here so all the plumbing would be in the foundation. I also thought about adding in and outs, outside the house for another 200 gallon "pond" to house the saltwater plants....
The possibilites are endless when you start building with the tank in mind...
If it ever happens for you let's see some pics.