I've got a friend looking for some heavy duty half chaps, preferably not suede. We've had a lot of trouble finding ones that last more than a couple months without being worn right through. The last pair of Sergio Grassos (sp?) lasted a whopping three weeks! He's been riding in tall boots lately but wore right through the thick (and very well done) patch-job that had already been done on his Vogels from the last big hole he made in them... Nothing seems to hold up!
So.... What are the toughest brands you've come across? He's on a good 10+ horses/day so they need to put up with a lot. A couple of suede pairs have also been tried (can't recall the brand names right now) but those were destroyed quite quickly as well.
I'd rather be riding!
I've had the same pair for at least 6 years. El cheapo pair, On Course, I think? Not even sure if they still make them. Unfortunately, they are suede. I throw them in the washer whenever they get funky, but I definitely haven't ridden 10+ horses a day in them. I just recently had to rip off the buckle strap at the top of one of them because the stitching had come loose. That's the only damage they have; all the important parts are A-OK.
The toughest half chaps I've ever seen were custom or semi-custom worn by exercise riders at the track. They were usually really thick, soft leather made by makers of exercise saddles etc. Try cross posting to racing and I'll bet someone can hook you up with a good source.