OK, there are my thoughts:

1) the sticker should be visible from a distance.
2) it should be pleasant to the eye.
3) it should double as an advertizement for the list.
4) it should make clear all VW boxes are included, not just vanagons.
5) a motto is fine, but not necessary; the shorter, the better.
6) window sticker may be preferable to bumper sticker.

Append or delete to this list, then find one (1) skilled list member (is
there a graphic designer in the room?) and delegate the job to him or her.
<Matt (no last name), for example, had offered his help earlier today.>

Sami