I'll tell you what... You post pics of the equipment in your possession and I'll send you an enclosure design, This thread has been all over the place as far as equipment goes. I'd be willing to help, but you'll need to post exact measurements, desired tuning and amount of power (amp/load). Also your skill level building and what tools you got available, so if you want a free design... Just get the equipment and say when you are ready.
I'll do what I can to help... lol
And a pic of the cargo area so I can see it myself... sorry... forgot to add that tidbit.