Hi,
I have a set of floor mats that came from walmart. They are really deep and will hold a lot of mud and water. They were not very expensive, and I found ones to fit the front and back seat floor boards. The front ones are a tad long, but its not bad. I also found a large square mat for the back. I think it was all of $7. there is about 3 inches between each side of the mat and the wheel wells of my '96 Trooper, and about 6 inches front and back. It would probably fit great in a rodeo. It also walls, and is good at catching spills.
Adam