I'm not sure who else has heard the Telefunken in a studio, much less had the chance of comparing it with other ribbons, but I did get to spend a half hour or so with it. I was very impressed.
The reason that you're not hearing about it, I suspect, is that it's not finished yet. There were three on display at AES in different finishes (they haven't even decided on which one to make) and we had two of them in Nashville for a Telefunken listening party back in November at Dave Martin's JavaJive studio. Below is a picture from that event.
They are finishing up the design. "They" meaning Jerry DeSilvia, a ribbon afficionado who has come up with this design, patterned after the BK-5. It will be badged Telefunken even though it's not a Telefunken (then or now) design. What else is new?
It sounds very good, regardless of the fact that it is cardioid. During this session (which was not mine), we put up all the mics you see (and added a Naked Eye to the lineup after this picture was taken) and compared them on upright bass. We did a fast calibration (peaks within 1.2 dB, all on the same performance) and then listened. For this solo upright bass through this preamp (all were through Great River MP2NVs) on this day in this room, the Telefunken sounded great. Easily the best or second best depending on who you asked.
Again, this was quick but very informative. Not only to me but the Telefunken guys who were there as well (Toni, Alan and several others). I gave them a few suggestions. We compared output levels with other common ribbon mics. They want to get more gain out of the transformer, possibly tailor the FR a bit more, but based on what I heard I encouraged them not to stray too far from what I was hearing now. As with most ribbons, it was far from flat but it sounded great.
Hopefully they'll be in touch with me about their progress since I'm very excited about getting one to add to my ribbon collection.
The mics below are (l-r) Tele RM, R84, Dave Martin's 77DX, Tele 47, R-122. Naked Eye not pictured. Photo courtesy of Alan at Telefunken US.