Loopy virtualization question

So, I want to be able to work anywhere, anytime on my pet projects. To that end I thought of using Virtual PC to have a "virtual development machine" set up, and sticking said "machine" on a USB hard disk.

Now comes the tricky part.

Obviously my personal machines can have virtual PC installed so using those machines is no problem, but is there a way of running up a virtual machine without having to install client software on the machine I'm plugged into? (For example, making the USB drive bootable, and somehow booting into a virtualisation environment which will then boot the VM.) Is there anything around that does this? (HyperV for example, as obviously VPC doesn't.)

Thanks.