I might end up using an older PC, or if fortune smiles, two new ones, to try and network render any tips on this folks? :)

I just tried that at home last night. I installed a RenderCow on my main PC, and one of the other 3 machines I have on my local network. Fire-up the main Vue , select 'Render with Hypervue' and add the 'cows'. Worked like a charm :) While my wife and I are at work, the kids are at day camp and while we all sleep at night, my own little cluster is rendering away. Example: one 800x1200 image, rendered in User mode with Radiosity went from 45 hours on my main machine down to 15 hours with network rendering.

hm, thanks for that tip Agiel :)) Oh nice way to end up with good radiosity type lighting fast n' cheap is... save your sky or even scene out as an HDRI...import back in and use it... saves a ton of time! ;)

Yes, go for it, definitely! Although, sometimes, the lighting is rendered differently from 1 machine to another, and the result is awful! Another Vue surprise!

One tip. The number of cows available when you start rendering defines the number of tiles. IIRC 2 cows = 9 tiles, 3 cows = 16 tiles. If you add cows after the rendering starts, the number of tiles will not increase. Why do I say this? Well it can sometimes be quicker on a relatively quick render to stick to 9 tiles, and add extra cows to work on that, sometimes the data transfer between the Vue host and the cows can be very slow, especially if it's a large ecosystem type scene. So more time spent rendering less transferring data across your network. It's a balancing act :)