Per an email I received last week, Nexus C-6 with Phantom control are disco'd until the new model rolls out in 1st Qtr of 2010.

I like the Sonos idea. Logically group the zones with 2 or 3 ZP90s to feed the 12 channel amps. Set the amps to line level detection. Based upon budget, then add several CR200 remotes, Ipods and/or PC control.