I made one of these for when I was a repair technician at a computer shop. They used WinPE, which is the same sort-of-Windows environment that installers run.

UBCD4Win was the toolkit I used. It had all my virus scanners, data recovery apps, pretty much everything I could ever need on there. Like a Linux live CD but with Windows. Shit was brilliant!

Windows still does WinPE, but I think that is limited to OEMs and other fancy Microsoft-licensed corpos.