The simplest approach to scaling of rendering is to render in the cloud using software that supports it. Then you don't need to care about the hardware or operating system or even the software licenses and just pay purely for the time. Unless you're running an animation studio, odds are you'll save money every time. In fact, plenty of animation studios work this way too. Just google "cloud render" to see the options.
Now, is Cheetah 3d going to support stuff like this any time soon? I doubt it.
Will this make the Mac Pro redundant? Nope — you still want to put the most awesome computer in front of your artist that you can, because a top notch 3d artist is worth well over $100,000/year, and anything that makes his/her life better is worth a few bucks; there's no point saving a few dollars on a shitty, unreliable PC when your artist is costing you $200/hour.