Alright, so I've been going through this idea through my head a few times.
Imagine the following:
1 computer running Win 7. inturn is hosting a VM box, running Win xp as well.
Is it possible to connect a USB to sata connection (See picture) that'll go directly to the VM Box?

I ask this because I'd like to make sure if I backup someone's data prior to working on it. I'd like to contain infections to the VM box instead of possibly infecting my own computer.