Depends what the situation is, Did you need this setup to be fully supported? in if there is issues are you going to be going to VMware for help?

If so and you want to use iSCSI you will have to setup "in guest" iSCSI software initiators which looks like what you were proposing anyway.

You are correct VMware only supports FC RDM drives for custer accross boxes, iSCSI and NFS and FCoE is not supported yet.

Below is a good guidle line document for MSCS withing ESX.

http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=103795...