Ah right, didn't think about running several Tor instances in VMs. I'm sure there are better ways to run Tor from VMs though, if you know how the protocol works just run instances of some program that runs it instead of running the whole thing in a VM.
Sure. You can also run many tor processes. Or you can use light virtualization, so there's not much overhead. But the point is that it's easy to create lots of Tor instances. Much easier than building a botnet.
