I don't have an example of the leather seats, but I used to do a lot of leather work and tooling. Leather is graded in ounces. I would think if you got boot or saddle weight leather it would be to difficult to work and would be uncomfortable to sit on, In this application. Several years ago I made a binocular case from some 9 oz waxed hide. It took days for it to soften in water, and even then I needed a 3 pound hand sledge to beat it into the form I made. Even after soaking a second time I needed a drill to poke the holes for the stiching. The case is tougher than hell, but I can't see setting on it for any lenght of time. If I were to do a seat I think I would use some of the "new" garment grade leather. I thought about ultra swade leather treated with scotchguard, It would be almost like a cloth seat with the advantages of leather and stain resistant. That is my thoughts on it.
