For what it's worth, I finally was able to install my Aquia II this weekend. What a beauty! It's like a work of art in the bathroom. It completely transforms the space and makes everything look modern.
Installation took about 2.5 hours for me working by myself and going extra slow and being VERY careful. It was pretty straightforward and the instructions posted by Terry Love were a nice help. Drilling the holes through travertine and slab took a bit of time but went easier than I thought. Hardest part was getting the white anchors in -- the holes were plenty deep but I couldn't get 3 of them flush with the floor -- about 1/2" still stuck out. I cleaned out the holes with a vacuum and tried again but still wouldn't go down. In the end I trimmed the extra plastic off with a knife. Also -- a couple screws were really tough to set all the way in. Almost stripped the screwhead doing it.
Installing the tank was a breeze, had it running in 10 minutes once the tank was on. It works great -- flushes everything just fine, very quiet and quick. Not one clog yet, may it ever be so (my Eljer clogged every other day it seemed!).
My only cavaets:
1. It's unfortunate that the hose can only be disconnected by removing the tank. My hose started leaking where it connects to the tank and I had to tear it all apart. Not a big deal, only takes about 10 minutes, and it's worth it to have such a cool-looking toilet, but it's something people should know about (don't be like me and re-use your old hose -- get a new one and it won't leak! ;-) ).
2. There's a decent-sized "lake" in the bowl, but (excuse the following frank discussion) if your bowel movement is large and/or not cylindrical, it will not be fully submerged and you'll get odor while you're on the toilet. Personally, I think this is a minor trade-off, and if anything will motivate you to not linger on the toilet too long, which isn't great for your body according to what I've heard from doctors. Just something to keep in mind.
Many thanks to Terry Love and Co. for the recommendation, for helping me with finding out if the Aquia would fit with my rough-in, and for the installation guide -- it is all very much appreciated!