I made an 8" subwoofer cabinet that sat on my tranny hump between my dash and bench seat. It sounded very nice but was rather bulky. You could make a console that comes up and over the bottom cushion of your bench seat. You probably wouldn't be able to slide your seat back and forth when done but otherwise, you could do it that way. It could be around 10-12" wide, have a flat top, flat sides that are contoured to fit the shape of your seat, and that's it in it's most basic form. 1/2" MDF or plywood could be used.