I'm hoping to do something similar to the way you can install Windows on a Mac's 'Boot Camp' partition, but then you can also open that partition as a Virtual Machine using Parallels or VMware from within OS X. That way for the quick stuff, you just fire up the VM, but for the more 'intense' things, you can boot into Windows natively. The difference here being I want to use Ubuntu instead of Windows. (Don't care if I use Apple's 'boot camp' mechanism or a third-party boot manager either.)
I have current licenses of Parallels, VMware and I also am running Virtualbox 4, but I don't see docs with any that describe this scenario. So can it be done?