I've seen active/passive inputs on acoustic guitar amps, never on a elecric guitar amp.
Danno:
Another vote for Boogie, but I'd think twice about a Mark IV. To me they are overkill - just too much control, too many variables. I played a Mark III for almost 20 years. Last year I swithed to a Mark IIC+, the holy grail of boogies. I like the lead tone a little more than on the Mark III. The best lead tone, IMHO is the original Mark I, but they really don't channel switch. You can either plug into the rhythm input, or the lead input. I thought about setting up a two Mark I rig, but my back vetoed the idea. Of course the Mark III and Mark IV give you the crunch rhythm channel (think Marshall) that the Mark II lacks.
Bill, tgo