This is part 2 in my aerodynamic MPG ramblings (Yes, I've already slowed
down and got 600 miles out of the last 12 gallon tank in my Beetle TDI)...

We've covered belly pans..

What about using one of those old-fashioned bug shields you used to see
mounted on the front of old trucks?  Those upright pieces of lexan perched
on the front of the hood?  Why not find one that's close in width to the
Vanagon and mount it under the front bumper?  I'm sure that would keep a lot
of air from getting under the vehicle where it encounters front suspension
components etc.  This would be more ideal for the taller '84-'85 Vanagons
than the later GL lowriders, of course.

http://www.thebugshield.net/Photo_Gallery/IMAG016A.JPG

Chris S.