Very interesting thread. I used to play conventional 6-string, but over the years severe arthritis took that away. I'm now quite happily playing bass guitar, but to be able to manage a 'regular' guitar would be a delight.

DADGAD & open tunings in general seem like possibilities. What about a tenor guitar (4-string)? They were quite popular at one time and can still be found. Maybe a variation of open tuning with such a wee beastie? If 3 or 4 chords could be managed; add a capo and many possibilities might present themselves.

I think I've just talked myself into doing some more exploring!