Have you checked out EZ-Dumper? I think thats what it's called. I don't know what their biggest model is but I know one of them can haul around 8,000 lbs. and can haul a Bobcat 873 no prob. It's all hyd. dump, don't know if elec. pump. I don't have a bunch of info about it (as you can tell) but I would try to look them up and see if you can find a dealer. They look like a well built trailer.
Go hard, go fast, or go home