I remember reading Mike Lavericks blog regarding running vSphere within another ESX - it ran fine. My assumption is that the NDA for vSphere is over and someone can answer whether VMware Workstation has any issues running vSphere as a VM and whether any guests can be run from inside vSphere?
It would be great to be able to run a vSphere ESX cluster within VMware Workstation as you currently can with 3.5 for testing purposes etc
For those interested in Mike's blog - http://www.rtfm-ed.co.uk/?p=1049
Thanks!