The vSphere 6 Hardening Guide is now (mostly) available. This post will act as a temporary placeholder for the xls documents until the VMware.com website updates correctly. (surprise!)
After the website is properly updated, the files will be located here VMware Security Hardening Guides | United States
**Update** The links on vmware.com have been fixed. You can get the guide from the website linked above. I have removed the files from this post.