Are your VMs running on Shared Storage or on a separate Logical Volume?
Only if the VMs are on Shared Storage or a Separate Logical Volume than ESXi can the Host be rebuilt.
If it is on a separate logical volume be sure not to overwrite that volume.
There is also some UNSUPPORTED methods of resetting.
How to reset the root password of VMware ESXi 4.1 and 5.0 | Bernhard Bock
Virtual Infrastructure Tips - VMware: Resetting the root password on ESXi 5 (and ESXi 4)
It seems your in a tough spot and i hope this helps.
-vFantastic