Niclas Borgström released a tool called VMVBU for increasing ESX Server VMs availability in a SAN environment. Quoting from his site:
The purpose of this utility is to make backup copies of configuration files for VMware ESX Server between 2 VMware ESX Servers connected to a shared SAN. The reason is for increasing the availability of Virtual Machines should a hardware failure occur. By copying the VMX-files (and changing the displayName) all the administrator needs to do in the event of a hardware failure on one of the ESX Servers is to start up the Virtual Machine through the MUI on the other host.
Download VMVBU 2.0.1 here.