Here's an inspiration that proved out okay....
I had hoped that I could find a set of the plastic euro trim bits that I
see on German transporters (the ones that mount between the taillights)
here in the states. But all that I found were very expensive (it's a piece
of plastic for gosh sakes) and really weren't made for the relatively
skinny US license plate.

see example pic (Not My Van) at
http://www.weidefamily.net/vanagon/Pending_Content/BodyWork/BackEndEuroTrim
(Custom).jpg

So, I took a quick trip to the Mickey Mouse house of modifications and
came up with the following:

1. Buy a set of used replacement vanagon taillights
2. section and enclose the rear (lightbulb enclosure)
3. paint them satin black
4. mount on the back panel.
Total Cost including paint = $18USD

Final Result pic at:
http://www.weidefamily.net/vanagon/Pending_Content/BodyWork/VanagonwBackEnd
USTrim(Custom).JPG

Thanks,
Brent