If you want wall mount, I might suggest a tank-type toilet, such as the American Standard Glenwall, pressure assisted. The tank type give you less of a 'commercial' feel to the bathroom. The pressure assisted works well. If you went wall mount with a flushometer, you have to plan that well in advance, because you need a 1" water supply all the way, and you would have to plan the entire water supply system to the building to accomodate 5 bathrooms + I assume an owners apartment. I do like the idea of the floor you plan, but realize that must be a waterPROOF floor all the way. Not enough to just throw down extra tile. Easy to do when you plan on it from the get-go.