Won't be making more; they were made as a favour/part of the deal for the sale of some cranks. I can email you a drawing you can give to a machinist, though.
EDIT: might look a bit weird on the outside, with a blocky part designed for another wheel, even if it fits OK on the inside.
You making more? or distributing print files? I got a rear spingle with a hg cassette i wouldnt mind converting