Originally Posted by: Vegas Wierdo... I'm thinking two of these A/B-Y boxes with the second one being plugged into the "B" hole of the first.

So, the box that runs the two 1x12 amps would receive the signal through the "B" socket of the first box. Then the head + 2x12 cab would get the signal from the "A" socket of that first box. Then I could cut out the smaller auxilliary amps at will... add 'em in when I like... and then alternate between the two auxilliary amps or run 'em both at once or... yeah!!! ...

That'll do it. Things get seriously out of hand if you want to allocate certain combinations of effects to each amp, especially if some effects get shared.

You may need to go with some kind of midi-controlled ubergadget. Too much tap-dancin' for my taste.