Regarding the so-called Z-bed, I put one in a few years ago, and don't
recommend it.  The installation is OK, and  the hardware supplied is
good.  The seats end up about 1.75 to 2 inches above the level of the
engine cover and floor at the rear.  I bought a mattress pad from
Z-products company that matched the seat/bed arrangement.  The problem
is that this leaves the mattress just plain hard.  Two inches of regular
foam rubber is not sufficient padding.  I recommend finding a weekender
seat/bed arrangement from a "retired" Vanagon instead.  The 4" pad used
there makes all the difference.

Chuck Hill