WOW all this talk on pop-tops and such has my head spinning, here let me
add to the posts and confusion..

I have a 1980 ASI riveria. (straight up pop top) from what little
information I can find on these they were built on the basic body
platform or sunroof models w/o the sunroof ( I don' think so)

CHC COuntry Homes campers followed ASI with the straight pop up roof.
but a more attractive roof 'body' not covering the drivers area

I've seen a great informational on a fella from Montreal installing a
BAY high roof onto his Syncro, this is the one I'm going to try first..

but if a BAY high top can be added, could a Bay ASI (straight up
poptop?)

my 1980 van ASI has an ABS plastic roof material that is nearly
impossible to repair cracks in (from sun, age, shrinking)
the earlier BAY ASI tops looked like a similiar fiberglass as the
westy's.  which means it 'should' be able to be 'trimmed' to match the
vanagon's roof curve, the width is already pretty darned the same.

as for the upper bunk, I'll go and look into mine tonight and see what
'roof treatments' were necessary for my 2" foam upper bed. to be flat.

it's not always about the easiest or obvious.   and I do feel that
nearly every jon,dick, and jane can do this kind of work successfully.
with the help of some friends..  (now if anyone is in the Central NY
area and wants to do a van roof conversion I'll lend a tall garage and a
hand, for the experiance and vw comraderie.