Just saw the release of the 28 July 2011 patches for ESX(i) and in the list fixed is this little nugget.

When you use Altiris DOS boot disk and PXE boot a
virtual machine running on ESX 4.1 with flexible
adapter, the virtual machine might fail to start when it
attempts to load MS‐DOS LAN Manager NetBind.

VMware is still supporting DOS long after Microsoft has sent it to the curb. I know several Fortune 1000 companies that still have DOS applications that they need to run that are critical to the business processes. What other top notch hypervisors support DOS still?