I originally went to Boomer to have the first prototype made up, that was in G10. He can't actually cut metal with his current setup so I had another person cut them out for me. Then I did all the finishing from raw blanks.
The stuff I put out are really "extras" from pieces I produced that I wanted for my knives. Given I only have two small CRK's I really only make stuff for smalls. Outside of this I run a business so time isn't always on my side. The CRK stuff is kind of my fun hobbyist escape from real life when I can.
Frankly I'm hoping someone else steps up and does make some large accessories. The cabochon would be a much easier accessory for the large. To make a backspacer for the large it is harder than the small and not just because it's bigger. I understand why Southard didn't make a full one. There is so much more machining required for a full and he charged $150 for his out of titanium! On top of all that maintaining the strict tolerances a CRK demands.
I know a lot of people want them for the large, I get the PMs. If this was my full time gig, I would certainly make them happen because the market is there (hint hint other makers). But these things are a SOB to make, truly. If CRK didn't pack so much blade into the handle they would be easier. But of course that is one reason I dig the Seb.