Thanks to Microsoft selling cheap Windows 7 upgrades I am upgrading all of my computers. I have 2 HTPC's, 1 fileserver, 1 gaming PC and 1 laptop.
The problem is that I bought three different versions.
The solution
http://www.windowsvalley.com/blog/creat ... ingle-dvd/
I've made an image with all versions both x86 and x64. I used the RTM images and this worked like a champ. I was even able to activate the Ultimate Upgrade copy my wife got at her school doing a clean install.