As far as I know, Prodigy can still only use one PMC2 in a project, but they are working on having more. As for lighting Using Crestron lighting, prodigy can support about 60-70 loads using the new EX dimmers......do you need bigger than this? While i'm sure you may, the majority won't. I've been in plenty of 2500-3000 sq ft homes that only have 30-35 loads throughout the entire house, inside and out.

A PMC2 has 5 IR ports (they claim up to 3 emitters per port, but even at 2 that's 10 devices), 2 Com 232 ports and IP control....I know there are some limits on the IP control, but I don't fully understand that yet. 

I think up to 3 tstats, if I remember right.

PMC2 also has one or two contact closures, but so should your Denon and/or PJ.

I don't know enough about Ra2 to answer questions. i know you could easily trigger scenes through a 232 interface, just not sure on the feedback. I just use the Crestron lighitng and its been fine.

Then of course, you can step up from Prodigy and do absolutely anything and everything.

There is a learning curve, but there are also programers and CAIP's for hire.