Take a look at
http://monkey-hole.co.uk/esa/os/
for very early beta versions of Windows, there are even virtual machines (for Microsoft Virtual PC) to try something strange like Berkeley 2.11 BSD.
A bit simple/poor boot screen also for Windows Chicago Build 73, although it's very rare:


To remember: There is also an interesting blog which covers a lot of different virtual machines: http://virtuallyfun.superglobalmegacorp.com/