That would cause popping when switching preamps. Ideally you switch only outputs to prevent this. Any of the usual suspects could handle this (e.g. GCX, CAE 4x4, Effect Gizmo). The trick then is to split your signal to three different (pre)amps. The GCX and others can effectively split to two only, so you'd need a separate splitter and things get more complex...Mesa High Gain Amp Switcher does all this in the box but has no MIDI. It's also fairly rare and costly.
