As other listees have noted, the Vanagon indeed has a front
anti-sway bar.  These things are also variously called
anti-roll bars and stabilizer bars, which is what it is
called in the Bentley manual at 40.2:
http://www.rb.com/volkswag/vv91/vv91.htm

This is not an area where VW has skimped on engineering and
some K-Mart solution will improve it.  (There are no areas
like that with Vanagons except for headlights, but you can't
get the good ones at K-Mart.)  Basic physics would suggest
that a somewhat top-heavy truck with any kind of spring
suspension will lean a little in corners.  Things to
do/check if lean is excessive:

verify tires are correct specification and correctly
inflated
verify vehicle is not overloaded
slow down