There is a Lotus Technote
about Lotus Domino support when installed in a virtualized OS on VMware. The Technote warns that there have been no performance testings from IBM so performance could be a problem.
I have hear from a customer, that while you can have several thousand Notes users on a Intel/AMD-box, in a VMware you will see the limit with 100 users, so the performance is degraded by factor 10 as a minimum. I would like to hear if you have seen similar results.