Well, I ended up working something out with Tone to modify the rear utility box he offers, into a sub unit. Instead of the hatch/door he has on the backside, I had him cut a 12" hole in the top side. Yesterday I drilled some starter holes for the ports, a hole for the wire jack, filled with polyfill, and mounted my 12" JL Audio sub in it. Sounds and looks great! I had to pick up a Polk grill which I will eventually paint black, but it still works out near perfect. Once I get the ports finalised, I'll post some pics.

That dual 12" hatch setup above is pretty scary looking. It will be interesting to see what the final results look like. Can't wait.