I finally took the time to fix my squeak. I used what is probably an excessive number of felt pads on mine, but the squeak is now gone. I basically put one everywhere that the upper plastic trim might contact the lower one. After I was done, I tapped the area around the heated seat switches, and found that I missed a spot, so I put a few more on the right side of that seat switch panel (where it meets the cupholder cover area).

It seems much more solid now - I followed Steve V's suggestion to get a felt "blanket" to line the inside of that tray that slides forward/back in the armrest so stuff in the tray doesn't make as much noise.

Much easier than bringing it to the dealer and letting them do their own version of trial and error on it!