New home installation coming this summer.

I've been researching many hours/days trying to figure out what is the best way to get a whole home audio system with limited Video distribution in my new home. I would be doing the installation as I have connections to help me keep it to local code and am not worried about that.

My house setup will be as follows:

An outside/garage zone which I will use a separate preexisting amplifier that I already have to power.
Kitchen Zone
Dining room Zone
Living Room Zone and will be part of the video distribution
Office Zone and part of the video distribution
Home Theater Room which will obviously have it's own A/V Receiver (preexisting) and will be part of the video distribution.
Master Bedroom Zone
Master Bath Zone

Probably add the following zones later but would pre-wire now.

3 Regular Bedroom Zones

I believe that I can achieve the distribution with the following components:

Russound MCA-C5 Kit
An Additional MCA-C5 added later for the additional zones
Monoprice 4x4 hdmi->cat5e switch (http://www.monoprice.com/products/product.asp?c_id=101&cp_id=10113&cs_id=1011310&p_id=8151&seq=1&format=2#description)
Myrobridge with the HDMI firmware installed
Additional keypads as there are only 6 included in the kit

As long as I'm not missing anything glaring in the above for distribution than all that is left is the sources. With the MCA-C5 this allows me to have 8 sources which are outlined below:
2 Tivo Boxes (The tivo would give me ability to stream pandora with control from one of the A/V destinations along with giving access to the cable music channels as well)
HTPC with ability to output multiple audio sources (up to 6) with 1 source being an HDMI source which could be audio or video.

The part I'm stuck on is the HTPC. I mostly want the multiple audio streams and I have seen that Casatunes exists as well as the Russound media streamer but I am not a fan of the cost of those devices. I believe that I could develop something on my own like a Winamp plugin that would allow to accept commands from the keypads and control a specific instance of Winamp (would kick off a new instance of Winamp for each new source requesting streaming) and would output the audio to a dedicated soundcard which is then attached to the MCA-C5. The Winamp plugin would also have to create and send the metadata via RNET protocol to the MCA-C5 for routing to the specific keypad. I am a programmer so I believe that I could accomplish this... as well as creating an android app for my android devices as well for a universal control over my home network. What I'm looking for and haven't been able to find is if this has already been created or if there is something else similar that already exists but is considerably cheaper than the Russound media server or Casatunes.

I have my audio files stored in FLAC format so it's important to have a player that can play that format.

Does it sound like what I'm looking for is possible and also staying at or near 500$ from something preexisting?

Hopefully I've provided enough details. Also what are the thoughts on the rest of the set up?

I look forward to your feedback.
-Brad

Thanks for the reply guys! Sorry it took so long to get back to you I apparently didn't get email notifications or didn't see them so again my apologies.

I have looked into Sonos and found that on a per zone basis it is pretty expensive. Additionally I wouldn't have control at the keypad level and therefore would basically need to have some sort of device available in each zone.

Can you give more details on what mkes it so great?
Do you find that 3 streams is enough? At the current time I think that 3 streams would meet my needs but as my children grow up they are going to have their own listening choices and probably want to be able to listen to their own dedicated stream in their bedrooms.
What internet streaming applications are currently available through the DMS and are they controllable via the keypads? Can more than one instance of these be playing at the same time? I don't see any mention of them to play natively through the DMS and that leads me to believe that they are played through AirPlay which then requires me to have an alternate way of controlling the playback (Am I wrong here?). Also the DMS doesn't really fit into my video solution that I'd like to implement.

I have downloaded some documentation on the RNET protocol and plan on using that to code with winamp directly or with a program that interfaces with winamp and will be able to control it from the keypads. I also plan on making an android app that would allow me to control any of my winamp sources from my device. I do have a lot of work ahead of me but feel I can put together something that fits my needs better than what is currently available and I feel I can do it cheaper.

I was hoping to find out if other DIYers are out there have come across the same thing and have any input on whether it will be successful or not. Knowing that the MyroBridge was created gives me hope that I'd be able to create something as well.