I know that the MC600 doesn't have a lot of supports, but in the case your describing, I think it is ideal. I don't disagree that the MS200 will sound better than the MC600, if the MS200 is at the output (so you run Cat-5 to where your amp or speakers are). But I cannot imagine the MS200 will sound all that much better if your stack them all up in a rack, side by side, and use their analog outputs. At least with the MC600, you have proper analog RCA connections.

Primary: MD600, MS200 (SpeakerLink to AES), Trinnov ST-2, Ayre V6-xe, Salk SS8 3x LRC.
Secondary: MC600 (whole house).
Zone one: 568.2, G57, MS200, Spatial Hologram M2SE.
Zone 2-6 (Awaiting assignment).