1&2). All I use is a 5 port Linksys switch to connect my 4 renderboxes together. I do feed the line off of that into my home router, but that is more because it had an extra port handy. With just about all of the distributed rendering apps, they have at least some ability to control things by using the OS networking substructure. The top end apps (which I haven't messed with as of yet) -may- require a legitimate client-server framework to function in, but from what I've seen, such a 'real' network is there more because you have several artists using multiple workstations, and it is just easier on all concerned to have one server with a hellatious RAID array, and keep all the resources to be used there. That way everyone has access to the same material, and you don't lose time passing things back and forth on disks and sticks. If you did serious video handling, you would also want at least the RAID array, and might prefer to have a server that is more for consolidation than anything else. Now someone building a 200 node renderfarm would need a client server setup, just to allow them to control the 200 other computers from one location. At the level of a 5 node garden, a KVM switch does that just fine. 3). As long as there is a remote render application for the OS in question, and said app uses something standard like TCP/IP to talk to the controller application, there is no technical reason -not- to mix the boxes. At our level, it's probably safe to say that one of the main driving factors is cost; if a couple of Macs are handy and will do the job, then there really isn't a good reason to spend the cash to build Windows boxes, unless the Macs are simply too slow for your needs.