serial0.present = "TRUE"
serial0.fileType = "network"
serial0.fileName = "telnet://127.0.0.1:10001"
serial0.startConnected = "TRUE"
This worked for VMware Fusion 5. Should also work on VMware Workstation.
For this to run on ESXi, you need "good" license.
ESXi's serial as "named pipe" is not really what it says - it's hacked so that created named pipes don't show up in VFS namespace. It only works as a bridge between two virtual machines.
Login via SSH.
Shutdown -> "halt"
List VMIDs -> "vim-cmd vmsvc/getallvms"
Power-On -> "vim-cmd vmsvc/power.on ${vmid}
/etc/rc.local.d/local.sh