I'm pretty sure Rapids has them. If your LHBS sells draught equipment, they probably get it from Rapids or Foxx Equipment. Ask them to order one for you.
IIRC, both companies have a 90o elbow tailpiece that'll fit any shank. You'll need a nut and neoprene washer, though.
Edit: I'm unfamiliar with the connection shown in your original photo. What I suggest above may not be of any help. For my part, I suspect I'll need more images before I can offer confident advice.