Help Needed with Render Farms/G5s/Mac Pros/FCS3

Hi there everyone. Recently I've been thinking of upgrading my editing facilities. I currently use SL and FCS3, and an Intel MPB, hopefully upgrading to a Mac Pro soon. My questions are regarding how I could go about setting up a render farm for distributed processing, but I have a couple of questions I need some help with; everything is slightly confusing at the moment.

With the relatively low price of G5 towers and Xserves these days, it would be great to set up a farm with a couple of them, but, the issue is, how would I go about setting one up to use with my favoured applications, i.e. FCP7, Color, Compressor?

Xgrid I understand allows you to set up a modern Mac system as a controller in order to distribute to G5s running older operating systems. However, it doesn't work with the FCS suite, I believe?

Qmaster I think only works with FCS3, so obviously cannot work with G5s systems as they can't run the required OS for FCS3 to run on.

I'm keen to take advantage of the cheapness of older Mac systems these days, while still being able to use the apps that I've set into my workflow; am I asking too much? Or is there another way to do it? If I've got something wrong, or am barking up the wrong tree, please tell me, I'm trying to learn as much as I can about this all.

Thanks very much for your time!