[tubbedII]

Man...this sounds like a fun project! I don't have any plans/diagrams, but how different is the rear bench of a Burb to the rear bench of a Blazer? If they are the same (Mine is 1st gen though), I can measure mine out and get you some dimensions and designs.

In my mind, you would use all the existing mounts mounts, arm rests and what not and have the speakers downfiring. It'd be a fairly small box, so maybe 8's would be best...but if you invertered the speakers (considering there was enough room under the seat for the magnet) you could possibly get a set of 10's in there.