VMware released hardening guide for vSphere 5. Public draft is available under below link. Anyone is welcome to post comments with findings or proposals.
http://communities.vmware.com/docs/DOC-19056
What is the most important, is in XLSX format which will definitely make life easier for admins and for those who want build their own hardening guides based on VMware docs.
Remember, this is Revision version not the final one, for sure few things will change till final version released.