the tank would be backing onto wall.

my worst fear would be a leak. tank or plumbing but it definatelywould look good

I've seen a lot...but that one made my jaw drop. Stunning!

Hrmmm. It's a cool idea and given the materials today, and unlimited funds it could probably be done. Having said this the question really is, just because you could do it, does it mean you should? The potential for absolute catastrophic disaster is there, especially with a gas fireplace, not only to the tank and it's inhabitants, but to the larger tank that you and your wife inhabit :) . Yikes. Cool idea though!

My thought was if the fireplace chages on fire the stand will break and put the fire out.
The biggest problem I can think of this is the heat from the outside face of the fire place heating up the tank quickly. A chiller I don't think could respand quick enough to cool the tank.