Or for the ultimate splitter for multiple amps and speakers .
The Crown OC-150A
I'm with you on that unit. Much nicer than the non-a version. Mine has the cabinet and rack handles (stolen from an amp). Unfortunately it is not wired to switch amps, just monitor them.
Amp 1 feeds the three speaker selects
Amp 2 feeds the headphone outputs
Amp 3 is for monitoring on the meters only.
Oh and those meters...sweet, adjustable and of course, would have accurate ballistics for their VU function and offers a peak reading function, too. Along with line voltage monitor option and peak hold a very versatile 'speaker switcher' but not quite versatile enough. Can't switch amps to the main speakers.