Is this a 1 1/8" threaded (internal) stem, or 1 1/8" threadless (external) stem?

I was able to barely force one of the internal 1 1/8" stems into a old Suntour stem shifter, with a few mods.



As far as the external stems (which you're probably using), the problem with the DT shifters is that they normally don't use cable stops.

Our local bike recycler/co-op gets quite a few stem shifters in. If it was me, I'd take your DT boss in, and tell them that you want to try assembling a stem shifter around it (and that you'll put anything you take apart back together). Then, try a few out.

You may need to do some filing to get it fitting right.

Generally I would choose DT shifters over stem shifters. I chose stem shifters for the green bike above because it had TT cable routing, and there was no practical place to mount DT shifters without doing some significant mods to the frame (plus it is hard to get claps for oversized tubes).