I've been using microsoft virtual pc to locally run multiple internet explorer versions on my web development machine.
Most the time I pull down the vhds I need from Microsoft here
however, I have not found an IE 10 vhd anywhere on microsoft.com. I've asked microsoft here as well.
Should I copy a windows 7 vhd and just upgrade it to IE 10 for now? cross my fingers it won't run differently on windows 8?
Since you're running Windows XP and already have a Windows 7 VHD, I would say make a duplicate copy of it and upgrade it to IE10. IE10 for Windows 7 can be got from here.
I would suggest you to upgrade to Windows 8 Pro as it includes Hyper-V and native VHD booting support. Native VHD booting is on Windows 7 as well. See this post. This enables you to boot multiple Windows OSes as if running on bare metal.
Let me know if you need further clarifications.