Hey Terje,
yes, some of us have expressed both the need for it, as well as the plan to implement it (if someone can find the time), see here:
I personally think it’s a big mistake on Onefinity’s part not to offer an optional 43 mm mount, because with such an “Euro” mount, one would not only have a variety of milling motors as AMB (former Kress), Suhner, Mafell, etc. to choose from, but also a drilling machine with reduction gears (for drilling holes at very low speeds).
These are very nice pictures you created! Do you also have the capability to mill this in aluminium? 
Or a lathe to turn it?
If not, one idea I had was that one could buy this 43 mm mount and file off the overhang until it is 80 mm in diameter so that it fits into Onefinity’s mount. It’s already 80 × 80 mm in size!