Thanks to @Leonov I was able to acquire a Staedtler Mars Technico 555 compass not only with Circofix inserts but also with the amazing Circofix handle.
The handle is an ingenious accessory: It could be screwed onto the insert and had a lateral window for operating the push button, turning the insert into a mechanical pencil.
On the buttons of the inserts it reads “W. Germany” so they must have been manufactured before 1989. – The 555 was the top model of Staedtler’s compasses. As far as I know the one shown here was the first variant; the later (without “Technico” in its name) had a different quick adjustment with levers which were much easier to operate.
The design of the inserts changed at some point. The first had a conical button and the later a cylindrical one; besides that the marking changed.
This set with the Circofix handle has the item number 555 30 SK. When I learnt engineering drawing in the late 1980’s I had the 555 00 SK with a 0.5 mm insert but without the handle.
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You just gotta love those old Staedtler compass sets 
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I have a few of these - it’s my favorite compass!
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They are really beautiful!
Every time I look at mine, I find it marvellous: such a simple yet efficient and effective solution.
And I also wonder why neither rOtring nor Faber-Castell tried to come up with a similar solution: FC manufactured their compass inserts in the same factory as Staedtler (or at least I assume so: the shape is identical, the threads are the same, the caps are interchangeable, even the imprints look similar), and rOtring hadn’t exactly an accessory-deprived lineup.
It is true that rOtring’s inserts have a decidedly different form factor and especially a shorter lead sleeve, but they can easily fit into the handles used e.g. in Rapidograph or Isograph pens, and those come in a million versions; I don’t think it would have been hard for the company to carve a hole in some of their handles, and implement a fully functional pencil in just a few steps.
[Or maybe such a tool does exist, and I’m just missing it as usual.]
Anyway, I’m vary glad that @Gunther now owns the full set of thin-lead MP inserts. 
Do you happen to have as well the 2.00 mm insert? I don’t see it in this set, but it’s common in other variants of this line of compasses.
You’re right – the handle is simple, efficient and effective.
I too would like to know why the competitors didn’t have something similar. – I’d love to know where the inserts were made.
I wonder how the handle came into being. Did something screw the barrel of a Rapidograph or Isograph pen onto an insert, thought about a way to operate the button and had the idea of the lateral window?
Yes, I also have the 2 mm insert. Here it is in a drop bow compass from Staedtler:
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