a roof bar would be pretty awesome it would just take alot of reinforcing

 

I have a 12 in a box in my Jeep and it takes up a ton of room . I would put a ten along the rear right or left side wheel wells in a box molded around the wheel wells to get the best sound with space. Mine pounds but takes up a ton of room so I keep my rear seat down most of the time unless I have to haul more than 1 person.

 

You could mount it pretty much anywhere, it really just depends on your fab skills and how much work you want to do.

 

My next project is to put a pair (or 3)of 8" subs in the liftgate, with speaker grills of course, and some dynomat inside the door. Also a couple of 7" screens, one in the liftgate and one up front somewhere, probably near the rearview mirror.

 

what about modding the 5 1/4 speaker hole to fit a good quality 6 inch sub.

you should be able to get a 5 1/4 inch sub too, but probably only cheap ones.

they also have fully enclosed amplified 6 inch subs that are fully self contained.

 

these look like they would fit under the back seat and if not they could be easily mounted to the roof

 

I built a box (for tools) under the back seat, about 1.25cf. Don't see why you couldn't pull that off for a speaker box too. I built the box separately (out of sheet metal I had laying around), cutting the floor out under the rear seat, and bolting it in. Its not fancy fab work, but make sure your box is completely sealed so nothing gets in and seal it where it mounts using good rubber gaskets (universal window gaskets is what I used). Oh and lots of going back, checking measurements and contemplating how it will sit. The hard part is gonna be figuring out how to keep it from being lower that the tranny crossmember. Mine sits long because of that issue.

 

i'm not sure about the amp but there are "truck boxes" thats a sub box but slim enough to fit behind the seat of a pickup truck. I had one in my old danger ranger tight fit but it worked and gave me some bump. not loud enough to hear me from 2 blocks away but it was enough to make the music sound good.