Well, I will release the Generic PC Workstation device as part of 0810, but until then,
You can create a new type of TV It has to be a member of the TV category under a/v devices. you can use wizard > av devices > add new device > create device template to do this.
Make it a GSD device
and implement commands for Off and On.
system("xset dpms force off")
system("xset dpms force on")
Make sure the TV is added, and it is part of the room.
You can then test it by going into the power menu and tapping display off.
If this works, then...
* The Display will shut off after x number of seconds, and will turn on when menu is triggered, unless set to 0
* You can send On and Off commands to the media director in events etc to turn the display on and off.