You know they are not that hard to make on your own. Basically, you get a GOOD material (sunbrella). We got a deal on 10 yard length from a supplier, but didn't need it all. Lay the material over the top from base of windshield to the top of the tail gate. Then take some more material and form it down from the top to the bottom of the door. It'll look something like the outline of a soft door only larger. Behind that, lay out a piece of material to cover the back half of the vehicle (behind the door area) covering the rear window area. We did our in an arc behind the doors up to the belt line of the rear area. A friend did his straight. The edges are sewn with the same web material that you make the tie down straps with. We have 6 tie downs (3 on each side) with buckles.
Best way to lay it out is to get a large sheet of paper. Butcher's use to wrap their cuts of meat in it (I don't know if there are any butchers left in this world). Brown craft paper works too. Make the pattern out of that before cutting the material. Remember to leave an inch extra at all edges for sewing. My wife used her house hold machine to down one for a friend.