i think it'd be rad to put some of those flats (the pioneers your referring to) under the seat or out of sight, so 2 under the seat and put one in the open and see how many people will believe you that its one 12"
im 6'3", and had 3 10" JLw6's behind the seat of my reg. cab silverado. Couldnt push the seat all the way back, but it was still comfortable enough for daily driving.