Just received the latest version of User Profile Central (UPC) today!
UPC now simply has a built in feature to create a VHD backup of the C drive!
One tick in a box and along with a backup of the selected user profile(s) it also creates a VHD disk backup on the backup network share.
To limit space usage (to not kill our storage) the specific share now is set to delete all files more than 90 days old.