Yes we sell a full kit like this:
Sick Bike Parts
So the nut spins on the remaining stud, but won't even come off? Wow that be stripped. A couple things come to mind since you can't get a nut splitter in there. Easiest would be to remove all the other nuts, have a buddy pull up on the cylinder while you turn the wrench in the reverse direction....this should put enough pressure under the nut to get it off. If that doesn't work, grind the nut off with a moto tool....or grind slot in the top of the stud and use a big screwdriver to take the stud out.
Indeed our studs are high grade 8.8 and nuts are good quality to prevent this hassle.