here's some info about some folks who make those things, if you
don't want to try to make them yourself:

Cloyce Buchanan
Triad Magnetic Van Screens, Inc. magnetic screen for drivers &
4155 Friendship-Ledford Rd.      passenger door (listed in JC
Whitney)
Winston-Salem, NC 27107          and screen for sliding door with
zipper
(910) 769-2427                   down the middle. the sliding
door
                                 screen is custom made for vw's.
it has
Front Windows (fibreglas)        a magnetic tape on the borders
and
 VS109 Vanagon ...... $34.95     velcro wraps around the sliding
hinge.
 VB108 Bus .......... $34.95     i have the above for my westy
and they
Side Windows (fibreglas)         work great! they also make mag
screen
 VW203 Vanagon & Bus             for rear hatch. also non-vw
screens.
   Sliding window ... $26.50/pr   <cwebb@teleplex.net (Charles
Webb)>
 VC590 Vanagon Side door          Jon Hathaway <jonr@empire.net>
   w/Zipper ......... $51.86
Rear Hatches (fibreglas)         Shipping Costs: 1 item ....
$4.29
 VW303 Bus .......... $47.03                     2 items ...
$4.67
 VR302 Vanagon ...... $47.03                     3 items ...
$4.90
They will also custom make items as well....