Handy focal length for Joel?

I am sorry to hear that, but if even the GXR is too big, then I am afraid that there are not many options. The GXR+Mount+EVF weighs in at only 500 grams if you combine it with one of the really small Voigtländer lenses such as the Skopar 35mm f/2.5.

If you need something with AF because of the arthritis and it needs to be small, then you may want to look into the new Fuji XE-1 (smaller than the XPro1), and put the 23mm f/1.4 on it when it becomes available.