Would be very interested to know what they would charge to machine some for you. To make that cheaper you could always separate the shaft and the axle by pushing the centre pin out and get the machine shop to only make the shaft part, cause that is the weak part, then join them back together to have half titanium (or stainless steel?) and half original cvd.

I did a bit of research into why the steering is not working with the titanium shaft (see pic) and it seems the centre of the universal (the pivot point) is not lining up with the centre of the pivot balls. This isnt a problem until the wheel tries to turn. So Im guessing if you can make a standard one fit (which you have) they should work fine in the rear to replace those pesky dogbones (only if you dont want any toe in on the rear, but I could live with that).

Anyway have a look at the pic, I worked out (roughly) by resizing the photo (i knew the axle must be 5mm dia) to get approx the size of the titanium shaft, since I had no measurements, I got about 4mm difference between the two.
The CEN cvd is 6mm between the bearing shoulder and the centre of the universal and I guessed the titanium one to be 11mm, but XMODFORUM could you please measure the distance as shown in the photo. I have a couple of ideas for modification......we wont give up just yet....

Cheers