Thanks for the thoughts.
  I didn't know the castings had changed on those tiny motors around model
year '99.  Also I didn't consider finding used diesel vanagon parts to be a
very difficult or expensive proposition, possibly.  To my way of thinking,
finding a junk-er diesel or most of one and then swapping in the gas motor
and Digifant II stuff (if your van didn't already come with it) seems pretty
'do-able' by even a very 'weak' 'enthusiast'...Not much 're-inventing'
involved...more of a remove, remember, and replace stuff from one to the
other.
    I removed the head and swapped camshafts on my 8valve 1.8 liter in about
2.5 hours, with the motor still in the van..so swapping the diesel parts to
the gas parts can't be huge work...And having hoses fit (sometimes) the same
air cleaner, no re-engineering of the interior, stuff like that...that seems
like it might kinda more involved when you go the 15 degree route..
  Of course, with the Rabbit-style gas motor, you aren't looking at more
than probably 35 hp increase over the WBX.  But dang!  if you are starting
with access to a diesel van, you could have a trouble free Vanagon for very
reasonable money and not as much work as I see Neil contemplating with his
swap...

  Don Hanson