Just to disagree here. I installed one of these units in my Westfalia. I
moved the power unit forward several inches so that it just cleared the back
of the head with the drivers seat fully extended. This left a 9 inch + gap on
the top of the AC unit to the edge of the poptop opening. I then fabricated
an oak cover to enclose the whole exposed area. I built the cover with a
series of 1 inch slats bolted together horizontally. This let me match the
contour of the van top and fit the edges to drop into the seal track. I then
bolted the cover to the seal track and the AC body. The cover overhangs the
edge of the AC unit by 0.5 inches. The result is a storage shelf and sitting
base when the poptop is open.

I extended the poptop closure mechanism rearward to clear the cover, but a
hand clearance channel could also have been milled into the wood. I then
finished the wood with a clear marine sealer and varnish so that it matched
the wool paneling that I use for a headliner in the Vanagon.

In the front, I used the Dremel tool to modify the contour to fit my wood
panel ceiling and shortened the transfer duct. I brought the AC lines up by
the drivers side post through the sink/stove cabinet. To clear the stove/sink
cover when opening, I used a router to open a smooth radius on the cover. All
hoses made by Hoseman locally.

This was several years ago and the system has worked perfectly. On a trip to
the "tailend-of-the-universe" (AKA south Texas, former home of
she-who-must-be-obeyed) in 95 degree weather, both front and rear passengers
were kept cool. The mpg hit of running the AC seems to be a wash against the
drag of running the Vanagon with the windows open.

Not bad for a former diesel.

Oh yes, the access to the upper berth has been occluded, but I have no
difficulty getting up there. If your girth is measurably larger than mine,
you shouldn't be up there anyway.

Frank Grunthaner