Good stuff here.
I take a different approach to this. I boot the ISOs directly from a FAT32 flash drive using grub legacy and memdisk. Using the raw ISOs lets me make a multiboot flash drive with both 32 and 64 bit Win 7 recovery "disks" on the same drive along with Ubuntu Linux, Acronis, Memtest, Spinrite, HD Regenerator, and some other stuff. Since it's FAT32 I can easily access it and modify it as necessary from whatever OS is handy.
Very handy for forensics and recovery. It takes a little more work, but for me it's worth it. When I get a chance I'll post a write-up over on http://www.beezmo.com/FloobyDust.htm