I think they are not complete clones, but yes, the only completely independent design seems to be the Kaliber
PS sorry for hi-jacking the thread with Nestler stuff
PPS background of the image is the Nestler manufactory.
Top to bottom:
What’s the OEM counterpart of that third piece? 
I guess the 3rd was meant by Ulfe with Staedtler 925 sibling. Of course the front part is different…
If I had to guess, I’d say Ueda — which was (?) probably some factory like Ohhira that worked on the sphere of Staedtler Japan?
Edit:
Ueda Pro 500
Herlitz 05
Nestler Pro 03
All these have the same dimensions and interchangeable parts, some are even identical (the first two). Nestler’s parts/materials are quite more refined though, probably customised from the ud-500 or ud-1000 models.
The mysterious UDs 
Are you aware of other models than the DD pros? The hypothesis with them as manufacturers for Staedtler jp sounds not bad. At least I am quite sure that Staedtler jp products are not manufactured here (Nürnberg I mean).
Not aware of other models, no… But like Ohhira, Ueda can be a larger factory, and machining MP parts is just one of the things they do (or did). I had an “Ohhira” that was the OEM of the Fuji Corona (and apparently they’re behind Manufactum MPs too, since the specs match quite a lot…)
Schneider in Germany is a bit like Ohhira, no?
It’s also reminiscent of the JavaPen Staedtler knockoff.
Apologies to the OP. We’ve completely hi-jacked this thread… 
You nailed it 
