Thanks for all the replies.

Alain;

We're already breaking video, PS2, and USB connections. It works great as-is, but I would like to simplify the hardware.

Luciano;

This one looks interesting. Thanks. The only problem I see with this approach is that a user could re-enable mouse/keyboard wakeup options once logged in. If there were some way to disable all input peripherals by controlling a bus signal, that would be perfect

Darrel;

Good points. Thanks. I'll look into what happens in suspend/hibernate. I wonder if networked PC's will drop-off the network in suspended or hibernate?