When Vmware release ESXi 5.1, the ability to migrate VM's from one host to another without having shared storage! Enhanced vMotion/Enhanced Storage vMotion. So yes...two ESXi hosts with only local data store, the VM can be bounced back and forth. However, the VM must be powered down first. Microsoft has Vmware beat here, MS allows running machines to be migrated. Also one must have vCenter installed, configured, and running.
Don't have vCenter but got a project that requires to move a bunch of VM's? No problem! Download and configure the vCenter Server Appliance. A free 60 day trial is included. It is NOT necessary to join it to Active Directory.
Update; with the Web Client one can migrate VM's LIVE across local storage. It cannot be done with the thick/C# client. FWIW, it is greatly faster than Microsoft's Live Migration, at least thus far with out truly doing back to back testing.