There's also PCE (I hate these names, honestly): http://www.hampa.ch/pce/pce-ibmpc.html

It even offers a download with Microsoft Xenix 8086, and even one with PC/IX, which is actually the Unix you could get from IBM itself.

Now, if anyone can provide a disk image with UCSD Pascal (one of the operating systems originally available for the IBM PC), that'd be super cool.