A thoughtful discussion yielded this question: if we wanted to create a virtual DMZ but have a method to also connect to the DMZ from "a" production VM, how would we do that?
There are some whitepaper about this:
http://www.vmware.com/files/pdf/dmz_virtualization_vmware_infra_wp.pdf
http://www.vmware.com/files/pdf/dmz-vsphere-nexus-wp.pdf
http://vmwaretips.com/wp/2008/12/05/virtualizing-your-dmz/
I assume that by production you mean a host that is not beyond the firewall?
If so, you'll need to configure the relevant firewall riles and Nat rules (if applicable) to allo access between the VM in the DMZ and the one on your side of the firewall.
If you are just talking about desktop access to VMs inthe DMZ, the way to do this is to allow users access through the VIClient - you can set roles / permissions to manage who gets a desktop access.
Lastly, if by your questions you meant accessing a DMZ VM from a DMZ physical server, then access would be exactly the same as you normally access between 2 physical hosts in the DMZ