Here's some follow-on answers:
I sometimes use Kaleidescape in secondary zones by having Sonos direct the audio feed to those zones. In the secondary zones, for the most part, I use Sonos which accesses CD content stored on a NAS (the same content that is also imported into Kaleidescape) and also use Rhapsody streaming of various genres (hits from the 90s, 80s or various #1 hits across several decades).
Sonos provides the best (in terms of cost, simplicity and implementation) funtionality for music choice and volume control in various parts of the house, as well as outdoors, which is why I basically have 2 separate music systems - Kaleidescape and Sonos.
Sonos is used in 2 ways - for the main level, I use a Channel Master 12-channel amp set to global that receives one audio feed that is directed out over the various channels. This sends music to the various rooms on the main level as one zone. The Channel Master is also used as an amp to control the outside deck speakers fed by Sonos. This is all wired to the same location. The front porch has another dedicated Sonos box that feeds that zones speakers. Other Sonos boxes are deployed in an office and a guest room, and other in the basement.
Volume control would be important for several of these zones if an AirRemote were used. I would consider purchasing a new multi-channel amp that could be centrally located and controlled through the AirRemote. Marantz has a ZS5300 and that box has 6 channels to control three zones. Crestron has their Adagio solution. The Marantz and a Kscape music player would probably do the trick to control the most used zones (main level, front porch, back deck).
I don't really use Itunes except on an Ipod and all the content comes from the music stored on the Kaleidescape using the Conductor interface. I don't really use podcasts, but Rhapsody is a really good product for what it is, although they really could improve the fidelity of their streams. I use it like a radio and prefer it over Sirius and XM Radio primarily because you can skip songs at the touch of a button, whereas with internet radio, Sirius and XM you're stuck with the song on a particular channel until it's over.
I would absolutely use a cheaper Kscape client for music/movies. In my situation, I would have the cheaper clients all over the house for use at those odd times when you need content at those locations. Because the locations are not used that often for music and movies, the cost justification is not there to add any other clients at the current price point. The movie players I have right now are used often, whereas the other zones would be used 10 times max per year.
I have an Iphone right now. Depending upon the speed of IR using the AirRemote, I would consider using an the ITouch as a remote in spare bedrooms. For music control, I have 3 Sonos controllers on the main level of the house. I can see wanting to replace those controllers with ITouch controllers. It saves looking around for the music controller.
Depending on the activity, I can see carrying around the remote, but other times it's just as convenient to leave it in one room and then pick another one up in the next room. Oftentimes I'm outside playing music, enter the house for some reason for a quick minute without the controller, phone rings and then a controller is needed inside. Multiple controllers avoids that problem. Same if I'm at the front of the house and wander to another part of the house. Multiple controller stations is ideal.
Jay