First of all props for pre-wiring!!!! even if you have to add some or if you have more then needed at the time! Some wiring is better then none!!! and Cat5e or Cat6 is great and a must!! via balins you can run about anything over Cat5e-Cat6 (including HDMI if you have two or more.).
You really have a nice MCE friendly set-up from what i see, Depending on how you want it to work....
if all the rooms have Cat5e your purty much set for MD's talking to the core. Just put in a Gigabyte switch at the termination point and plug stuff in. Bam, you have video w/HD capabilities, phone, security, lighting, temp controls, ect... (assuming a properly setup and compatible Core of course.).
now on to audio....
first i would find out are the speakers 2-4-6-8Ohm or 70v? In the media room are ohm type speakers prob, but the others idk.
now how do you want it wired?? i'm not sure quite what you mean by "Master" "Subzone" those are common but general terms. I'm guessing you are looking at one of three main setups.
1) all room speakers play the same thing, volume is controlled via wall mounted Vol controls or controls back by the amp, the media room is separate.
2) all room speakers are separate, (separate level and media, ect...) and of course the media room is separate.
3) a combination of the two
[By the way, the dif in an Ohms type setup versus a 70v is basically 70v can be feed to many many speakers daisy-chain style, the number or speakers
depends on the amp power, any and all speakers can be controlled using volume controls without the need to run home runs. The downside is quality.
70v tends to not carry the full spectrum of audio, so less highs and lows mostly and mid range mix. And its unpractical for stereo and VERY unpractical
for 5.1 systems. Ohms Setups on the other hand can only have 1-3 (in most cases) speakers per channel (most amps are two ch) but they tend to be
more gutsy and carry the full range of whatever you put on them (you dont see a lot of 70v subs do you...). But since it's only 1-3 speakers per channel
it's easy to separate out rooms, making it more flexible.. So if you want it to sound like listening to the radio in each room 70v is fine. If you want it to
sound like your in a small theater in each room or separate your sources Ohms is the way to go.]
Option one is easy, the core can feed music to either a 70v amp that feeds the speakers, or split off to feed multiple amps feeding an Ohms type setup.
Option two is a bit more complex, you will need feeds from each room's MD the the amp for that rooms speakers. You might be able to use the RG6 for that
(assuming it all terminates in the same place). Or go and pull your wires down to your MD and put your amp in the same room. This option gives you
complete control and flexibility.
Option three is either use all Ohms type setup or a combnation of Ohms for rooms you want control of and use 70v for rooms where you want the same
media to play.
In all options you use whatever 5.1 system you want in the media room and run it to the MD for that room.
The Ohms option;
price goes way up
need for feeds from each MD
The 70v Option:
Price goes down
easy to get sound in all locations with existing wiring.
good for background type sound.
one or two amps
only one signal per amp/channel
Lower quality sound (but still good mind you..)
all that said i dont see a way to do it without some sort of amplification. (idk if squeezeboxes or any other options provide internal amplification or what-have-you...)
also they do have subs for 70v, and they have 5.1 Ohms type amps. as always there are exceptions to every rule. And i might be missing something or there could be something better for you that someone else knows of (hey thats why its a fourm, two heads and all that....)
This is my 2 1/2 cents, take it or leave it. :-)
(also if your looking for equipment i can hook you up)