Are you looking for something like this (pag. 143 in the attached)
Using Serial Ports with vSphere Virtual Machines
Connect over the network Enables a serial connection to and from a virtual machine's serial port over the network. The Virtual Serial Port Concentrator (vSPC) aggregates traffic from multiple serial ports onto one management console. vSPC behavior is similar to physical serial port concentrators. Using a vSPC also allows network connections to a virtual machine's serial ports to migrate seamlessly when you use vMotion to migrate the virtual machine. For requirements and steps to configure the Avocent ACS v6000 virtual serial port concentrator, see http://kb.vmware.com/kb/1022303.
Yes, I've seen that thanks.
I was hoping for small scale another option would be feasible, but it is beginning to look like a vSPC is the only solution.
it's the only solution that lets you have a standard vMotion.