Very timely topic for me since I have just acquired a Barnack III camera, and I was looking for some LTM lenses.
I do have the Chiyoko Super-Rokkor mentioned above, mine has a "slipery" focusing action, but the main inconvenience, for me, is its clickless aperture ring.
Nevertheless, I have also bought, for this Barnack, a collapsible Elmar 50/2.8, but, appart from that, I still want a 35mm and a 28mm. And quite tempted by the Voigtlander 40/2.8 Heliar - which seems to have reached its EOL (could not find a new or used copy in Europe).
So I will keep an eye on this topic, as well.