Well for starters OS/2 Warp 4 (tried this myself) and it says it will not run any version of os/2. Tested with the lates version of VMWare Workstation 3.1.
Here is the official word from VMWare: http://www.vmware.com/support/ws3/doc/ws31_guestos a2.html#1025242
Here is the official word from VMWare: http://www.vmware.com/support/ws3/doc/ws31_guestos a2.html#1025242