All you need is a water cooled Vanagon parts van along with this:
http://www.thesamba.com/vw/classifieds/detail.php?id=1903636

A better idea might be to put an air cooled engine back in and use the
rebuilt Subaru in a WBX conversion. This package is only worth about $5k for
the van and $2k for the rebuilt Subaru though, since air cooleds don't sell
for more than $15k from what I've seen.  I don't think he really knew what
he was getting into though, or he would have cut out the front panel before
he painted the van.

Stuart