I haven't done this but would have thought as long you have your RDMs on a SCSI controller with SCSI Bus Sharing set to Physical this would be work.  Making necessary changes to share the LUN to ESXi host(s) and new physical servers.

Edit:  As you have a MSCS on ESXi you may have seen this already, it covers a cluster in a physical and virtual machine scenario, so the requirements may be relevant to you.

http://pubs.vmware.com/vsphere-50/topic/com.vmware.ICbase/PDF/vsphere-esxi-vcenter-server-50-mscs-gu...