Plus, in some cases (like, say, when I have dinner guests) I'd want the same music playing in the living room, dining room, and kitchen -- can't do that (or at least not well) except with a stronger amp, fed from the basement.

The idea of linking multiple receivers to play the same music has been discussed here on the BBS before. I don't know if they're planning on implementing that as a feature or not. I agree that it would be important for a nice dinner party, and would bring the whole thing together so that it would work better as a multi-room system.

Personally, I would like to be able to, from any given receiver's panel, be able to choose which receivers are "linked" together (by name). I could walk up to its panel and say "Link Dining room, Kitchen, and Hot tub". Then, after that, the dining room, kitchen, and hot tub would have identical controls and displays. The server software would need security to allow this to be enabled or disabled, so that the hotel in Ibiza doesn't have a problem with the guests.

But the lack of this feature wouldn't be a deal-breaker for me, I'd still do the install even if I couldn't link them. I don't actually need the same music in all rooms, even for a dinner party. And for rooms where I'd commonly listen to the same music, I'd just use one receiver hooked to multiple speakers.

(it looks nice, but not that nice...unless I could rip it apart and fit it inside the wall...hmmm....)

I have considered this. My example of the hot tub is a real one. I want a separate receiver to control from the hot tub. My only restriction is that I don't have a good place to put it so that the display is visible from the hot tub. The player is too deep for the kitchen windowsill. So instead, the receiver in the dining room is the same receiver that runs to the hot tub, and I use an IR repeater to change its volume and do prev/next track from the tub.

If I were building the house from scratch (like you), I would simply design every room to be music-friendly and have a proper attractively-designed shelf/sideboard/alcove for things like stereos, and there would be a proper weatherproof alcove out by the hot tub.