My pics are somewhere on here. I've got large amps underseats. you've got about 23" of width to play with. height isn't toomuch of a problem, depth is sufficient for most chassis.
AS far as wiring goes, power is ran along the driver's side under the doorsill to a dist block, then to my subamp under the driver's seat, across the back/underside of the console to power my 4ch under the pass seat. Grounds for everything in my car are pulled from under the bracket at the rear of the console. Rca's run down the pass side doorsill 2m to the 4ch, 4m for the sub amp which goes over the hump just behind the shifter. speaker wire for the fronts runs up under the console and under the carpet to the kicks wher eit's run straight to the doors.
ANd for the additional fun. my power/ground/switched signal comes from under the console (couple relays goingon tucked inthere) to work switching for my carputer and screen. Audio goes through a digital coax down the pass side prettymuch along the RCA's up to my deck.