It wasn't a VirtualBox limitation, but an OS X... I know that VMWare won't let me create a VM of 10.6 unless it is from 10.6 Server install media.

Whatever your reason, you can actually install and run OS X on any Intel-based Windows PC with a program called VirtualBox. Here’s how.

Target disk mode The easiest method, if you have access to another Mac with a DVD player, is to use FireWire target disk mode to install Mac OS X 10.4. Use the following process.