alright there is a design i came up with for 5 mojo 15s and 5 memphis 4kws to be squeezed into a 1985 s10 blazer. its almost exactly to measurement but is subject to change a little. 15" long external slot port tuned to 38hz.
this is like TommyK says. "Fitting 10lbs of $hit in a 5lb bag"
the way it is designed wont be able to sit extremely comfortably like i would like in the blazer cuz the box comes to the front of the bpillar but this would only be drivin like once a week if that.
just a rough sketch but almost to each measurement that its going to be.