While it would be nice to have a 7500 gallon tank off the living room, I don't think I'm going to build another one until I have this one up and running. I still have the current pond and the expansion tanks to keep me busy too.
I do have a design in mind for a hexagon viewing room with spiral staircase in the center. A recliner would be on a circular track and motorized with a toggle to go left or right, so that you could go around and view any of the 6 windows without getting up. There would be cushy seating benches in front of each window wide enough to take a nap on. One side would have acrylic on the inside and outside wall. The outside wall would be shared with the living room and viewed from there. Of course, this house doesn't have the space to build a 100,000 gallon monster like that. One can dream though.