Back in 2005 Mackie released the Big Knob monitor controller to make managing multiple monitors much easier, now they have extended the range to make using multiple monitors much easier and affordable.
The new range encompasses 3 new versions of the Big Knob, Big Knob Passive, Big Knob Studio and Big Knob Studio+. The main difference to the Big Knob Studio and Studio+ is the addition of two onyx mic pres.
More info at Mackie
Emulate multiple mics, change proxmity and axis on the fly with UA Hardware