I want to start by saying that I am familiar with Pluto for about 10 minutes... but I love the concept.
I just spent several weeks designing a complete Home Automation system utilizing Homeseer, NetRemote, JRiver Media Server, etc for a new house that I am building. During the process, I began to acknowledge the fact that given where current standard HA thoughtprocess is, there are MANY sacrifices that one must make to implement a system that does what we are asking of the multi-channel sound AND have video/security/climate/lighting all routed through the same interface. Which leads me here...
One option that would be family inexpensive and effective would be to add several low-cost thin-clients to the wiring cabinet. This would allow multiple "sound channels/zones" to the system. They would, of course, need to be synced where they share a single source.
The biggest comment that I have here is "linking" each of these thin-clients to the "active" thin clients in each room. They will need to be done this way to "share" a configuration with the active client in each room (if there is one?). So dual functionality might be required here. As long as you can identify each thin client as a ZONE (family room, kitchen, all-on), whether a partner to an in-room DMR or standalone (outside deck, for example).
Still, the idea of establishing the true software capability within the CORE enables use of M-AUDIO 10 channel sound cards (3-4 of these allows for 40 channels!). At some point do you run out of processing power within the CORE to enable VIDEO to 5 other zones on top? That is another topic but the idea of having seperate "thin clients" in the WIRE cabinet is the only solution that I have come up with based on a more traditional approach to whole-house audio. This doesn't contribute to overcoming the software issues of integration to a multi-channel synced solution, but is a workable solution that I have resorted to in my current project... unless we come up with a solution quickly
Maybe my next project...