Burtons does the outer, but it's my understanding that no one makes an inner. I redid the slots on mine (mk1 style) via hardwelding and grinding, but the slots on the 2 are too small/thin for my tools. I'd also be worried about deformation due to heat from hardwelding with such thin slots. You would likely need (at a minimum) to pull apart the inner hub by grinding the rivets, pulling the backing plate, and the journal bearing off (they're all separate pieces). so that someone could cut it. Fly cutting with a carbide tool would be a reasonable (albeit time consuming option) that could be done on a home mill.
Newby's replacement kits are one of the only options other than running a suzuki clutch or other japanese clutch as a few people have done (it's a fair bit of fab work).