By reading ao many posts and those asking "how can they do that" It only leads me to believe that most of the ppl reading and asking questions are Really young, (hey nothing wrong with that) but MS and others have been shipping/making dvd single versions with 4 or 5 or upto 8 versions of Whistler (XP) and Win2000 and Vista for several years. yikes I have several old DVDs that have 6 to 8 full length movies on the... one std DVD with 10 versions of Vista on it.Yep, buddy! That's what they provide in physical delivery pacakages for subscribers. As an MSDN Premium subscriber, I truly know about it and have quite some discs made in that way, dual layer D9 DVDs containing both 32-bit and 64-bit of Windows Vista w/SP1 and the same for Windows Server 2008.
Also keep in mind that it's not the first time they do this kind of trick. Microsoft had released system image collections of Windows XP SP2 and Windows Server 2003 SP1 within one DVD disc years ago. When you boot with that DVD, you will have a menu to choose which system you'd like to install.
Kinda save resouces
Guys and gals, you do not need BlurRay or Doublesided HI Densidity disks to do this. It is EASY if y0u know how.
yikes a. 2g VHD is over 5GB uncompressed and the STD DVD will hold that and more to make 2 versions of 5 to 8 editions/versions of Windows 7.