No, a VMware's Fusion creates a proprietary file that contains the the OS and apps. If you want to run windows in bootcamp, you must partition your drive and then install windows from a windows install disk.
conversely after installing windows via bootcamp, VMware can use the BootCamp partition instead of their proprietary file structure. So in a sense its close to what you're asking. One windows install being used from BootCamp and VMware.
I believe it is...
when VMware is running and you connect say a thumb drive it asks you if you want to connect it to VMware or Mac. when connected to VMware i can use the VMware os, in this case win 7 to format the thumb drive etc.
I'm thinking it may be possible to create a bootcamp partition, eject it with disk utility, then mount it again?