Are my eyes deceiving me??? Are we actually talking about a switching box that swaps the input into your pedal board? How difficult is it to unplug one guitar and plug another one in? I assume you are actually going to have to walk over to your guitar stand and remove the guitar you are playing anyway, so why not just unplug it too?
This is just pure laziness...
Anyway, which A/B box is best for this... Sounds like a good idea.