Recently I made a westy cover out of $1/yard tyvek. I love it. Here are some
thoughts:

1. It will roll into a small ball and stash under the seat or in a closet,
which is great.

2. It takes exactly 40 yards of 40 inch material (look on ebay). You will
have only a few square feet left over.

3. You almost can't tear it.

4. You CAN burn it. Ask me how I know. Turn off the light on your sewing
machine and use some other light source.

5. Amazingly, it holds water like you wouldn't believe (it has a very soft
feel, seems like water would pour right through). You have to leave an
opening in the "luggage rack" to drain it or you might not get the cover off
the car for a long time after a rain.

Jim