Had an ingenious idea today!
This may not work on all vehicles, but there are few smaller tire sized vehicles who could get away with this!
26" Twister Saucer Disc Sled by Pelican | Plastic Saucer Children Sled | Snow Sleds For Kids | Toboggan Sleds - American Sale
If you buy a standard Kid's Disc Sled, you could cut it in half and have a ready made, bowed, wheel skirt! My Subaru has a 30" diameter tire, this sled is 26". I bet some smaller cars like Escorts, Geos, Matrix, etc could utilize this method.
Figured I would share with the rest of the class.
PS Here is a follow up
http://www.homedepot.com/h_d1/N-5yc1...atalogId=10053
Not as aerodynamic, but this is a 28" Disc.
