Hey JustDavidP, your vacation is over (wondered where you disappeared to for a while there), but this thread is still waiting for your promised thoughts and ideas...

I got permission from Angel to cut another large hole in a wall, this time to fill with another tank.... Thinking it might make for a great pony corral since it'll be viewable from both sides, the dining room and her office.

Thinking medium sandbed a little rock, lots of plants, and low flow. Lots of questions about water quality to best give the best home possible.