I’m curious what your comment was about an '08. I have on '08 GP Racing chassis, which is actually CRG. It also has the 80mm spacing. That said, it’s just a 0.25" aluminum bracket with 5 holes in it. It should be fairly easy (and cheap) to make one with 4 holes for the cassette with 80mm spacing for the 2 caliper bolts. I assume it all looks something like this: