While Googling for the same desire(instead, I have Linux/Win as dual boot available hosts) considering to abuse Yumi for it.
I found Easy2Boot(easy2boot.com), what looks promising. http://www.msfn.org/board/topic/162640-install-all-windows-install-isos-from-1-multiboot-usb-drive/ (R@Buscar below, np. and I agree, dead url's can be frustrating. It's a forum topic about the Easy2Boot tool including TY vid. https://www.youtube.com/watch?v=MBKh_jDyTmQ & *NotEnoughReputaionPointsForrA3rdLink=____youtube.com/watch?v=YyQ7xSvVMHE)
I'm about to try it out.
Maybe you can run Windows for it under the open source virtualbox.org/wiki/Downloads