the_bluester: One XBMC install acts as a server to all the others, but it is possible to sleep both when not in use. If you use v13-based builds, XBMC also has new advanced wake-on-lan features that will wake the other HTPC in order to use that UPnP library.
The wiki's
MySQL (wiki) instructions currently just cover the normal XBMC library, but there is MySQL support for PVR-related databases, IIRC. I'm not sure how to set that up, though.
dfelice81: Typically, we don't announce release dates far in advanced. We don't want to get people's hopes up if we miss a date or cause confusion, and at this point even the internal Team knows that the actual date can change very easily.
That being said, a rough estimate based on past releases would be one year from the last release, which was in Jan 2013. Just remember, it could easily be longer or shorter than a year from that. Off hand, I actually forget what the internal Team date is that we're aiming for, so I literally can't be any more specific than that :)