There's one free program that will actually add XP and ubuntu into the 7 BCD store you may have heard of called EasyBCD. Originally written for Vista you can use that program's form of NeoGrub to load Linux.
The tip for seeing a dstro added in as an option is not to allow Grub to replace the Windows mbr there. You custom install the intended distro and when prompted make sure the root partition(Linux system files) is labeled the "/" mount point making sure to check off the "do not install Grub into bootsector" box.
You can download the 1.7.2 release of EasyBCD from http://neosmart.net/dl.php?id=1
The general information with several guides is seen at http://neosmart.net/wiki/pages/listp...ageInHierarchy
The one thing to note about EasyBCD however is that once installed and you start configuring the other OSs the new 7 look for a boot splash screen will be replaced with the one for Vista.
It does just as well on 7 as found out on previous occasions while testing the 7 beta builds but still has that one drawback and why you may prefer the virtual machine idea better!