I think I have a great solution after tons of trial and error; I'll take pics tomorrow. What you do is get a rubber backed low pile area rug at Home Depot, which, remarkably, is just about the same size as the flat area (when it gets dirty, simply pull it out, shake it, and run a standard home carpet vacuum over it). Then, buy 3 oversized bath towels (40x70). One to put over the flipped up back seat, and one to drape over each seat, 4 plastic clamps, 2 for each seat to bring the front part of the towel together with the back. Then, a small towel over the center console. Also, somewhere on Amazon are these protectors you slide into the rear windows that will cover the interior of your rear doors. When not in use, simply slide the towels off the front seats and let them drop behind the seat, then simply slide them over again when you need them.
I've tried a ton of those sling type protectors, they're all limited and they don't cover nearly the areas that need to be covered, the towels will, and simply toss them in the wash every week or so. I have a German Shepherd that drools a ton in the summer and goes swimming on occasion, and this method works great.
Edit: I found a pic.. Eventually I bought matching off-white towels so it also matches the interior.
