I have speakers wired into every room
The cabling returns to a small server room.
I have 3 multizone amplifiers which the cables are attached.
Which are installed in a PC with 3 M-audio Delta 1010LT audio cards.
And on the PC I have an application called Commandcubes which is no longer updated or supported and is a bit flaky.
I have pc's in most rooms and various handheld devices to provide control, but the playback has to occure on the PC/server rather than on the controling device.
I think you would need to be more specific. Please describe exactly what you want to do.
For example, personally, I access MC on our HTPC/server through a remote desktop program when I want to control its two playback zones remotely from another room.
The HTPC/server machine is in a home theater room downstairs and we have an audio only Hi-Fi system upstairs. The upstairs system is connected with the downstairs system with two separate audio connections. One is parallel with the downstairs audio output so it provides an easy way to play the same output simultaneously through both systems. Another connection comes from a secondary audio card and it can be used when two MC zones are playing individual playlists.
At other times I use the HTPC as a file and database server only and play files through local PC & MC instances in other rooms.
In any case I use a fully featured PC and MC as the controlling interface (I don't like limited remote controllers).