As far as I'm aware, they are commissioned by the dealers for their particular territory?
I know that, for instance, there have been runs of British Racing green, Noir, and Candy Apple Green and Candy Apple Purple, for the UK, Japan and US markets, respectively.
Would it then be possible for a group of individuals to club together and commission their own custom build, or is it solely for dealers?
It does seem to be a bit of a "thing" these days: there are new Limited runs being released all the time, it seems...?
I really liked the Candy Apple Green 4003's, but they were a USA-only thing, I think? And I only found out about them after the fact, too...!

(Not sure if Andy Babiuk would ship to the UK, either..?)