Ah, okay, I'm with you, it's 2 servers on 2 machines, each as only one zone.
do you find yourself wanting to use a theater view experience in 2 locations simultaneously? I only have one machine, and 2 zones, so I only need/want the 5 button for theater view in one zone, and the webremote type control for the other is fine in my case.
I'd much rather see MC move to allowing multiple "library" connections to one server. with "library" really being a customized client setup.
so, your server machine above would run the server portion of Media Center, and each place an interface is requested/shown (the 2 HTPC's and the Android device you show) is just a client.
the only library server is just the entire MC back end. it handles all library organization, knows the locations of all media, and just presents that to each machine, and each machine can have a different "library" (client), including view schemes, playlists, ratings, etc.
One machine handles all of the reading and writing of the actual media files, makes this full list available to all clients/machines, and all other machines just tell that one what it needs. all the meta data (much of the current library information) is stored on the server machine, when another machine connects, it asks which client, login, get your personalized experience.
However, wishing for the above isn't going to fix your request today (but would resolve that issue if implemented), so hopefully your request can be implemented soon.
Hopefully Gizmo continues to get some more development time to get a few shortcomings ironed out and polished up before we move on to v16.