I have a 4th axis machine, you can make figures with it by cutting some parts off, arms that stick out and such. If you plan ahead you can make it work. It's easier to have figures made using Rapid Prototyping machines though. Both methods have their advantages and limitations.
There's plenty of RP suppliers with machines of varying resolutions.
There's no limit to how many slices I can cut a piece into as far as I know. So if you wanted, you could slice your model into what would scale to 1" slices in the final size, cut the profiles in 1" foam on a cnc router, stack them up and have your basic shape at whatever size you needed. It's a fairly popular method for scaling up to monumental size.
I can also define cut lines and cut parts off, like arms, hands, whatever, add a way to register them, mill them seperately, then reassemble.
A 3 axis mill could cut any part of up to a full sphere, a half at a time. The limitations in the size and surface finish are defined by size and accuracy of the mill and the cutters used more than anything.