Mesa Boogie Midi matrix will control the amp switching through midi. (without having to mess with those external switching jacks)
The Voodoo Lab PX-8 has a bunch of effects loops that can be turned on and off and configured by midi. Those two will do what you want to do however, you will need a third thing to send the midi to everything.
Some of what you need will depend on if you are using pedals or rack effects.