http://cgi.ebay.com/Cats-Full-Steeri...-/350233702155
Is this the type of thing that you're looking for? Something to keep the steering wheel cool? If not and you want one that fits snug around the whole wheel, why not make one like a small round fitted sheet? You could still piece and quilt it, just make it about 4" bigger all the way around than the steering wheel. That should provide enough room for a small casing with elastic.
Now you've got me intrigued and I may have to see if I can make one before I go to Texas.