Not sure if this will work... but... (YMMV - disclaimers apply)
I recently moved, and in the new apt my father in law was putting in a new counter top and sink... and when we wired up the garbage disposal he used a pretty neat device instead of the usual wall "light" switch convention.
There is a small plastic/chromish push button (kinda looks like an arcade button actually) that mounts in a hole on the sink next to the faucet control thingie... it has a tube going from the button down to a black box that plugs into an outlet under the sink. The disposal then plugs into that box. when you push the button once it forces air/vacuum down the tube to the switch which then allows current to flow to the disposal. A second press of the button tells it stop.
Anyways with clever mounting and simple wiring you could uses this to turn on your cabinet... although I just realized you'd still have to get the pc to boot, wich would be another relay anyways... doh..
Since I spent all this time typing this up, I'll post it anyways, as it could be of some use to someone (at least as a better way to wire a disposal switch) but still think there could be a way to utilize it to some effect in a cabinet setting...
rampy