As the whole aim has been to sell new frames, forks, wheels, tyres that none of us really need – I am guessing the answer is NO.

For completeness – My wife has a 26″ full sus frame with a really nice 140mm Kashima Fox Float Factory (32). It would be great if it could be stripped and rebuilt into a new 650 lower even if the travel was a little shorter.
I am assuming Fox will have made sure this is not possible but in theory (at least) it should work; any views?

if you don’t plan to too massive a tyre in there it’ll probably not even need new lowers; 700×40 fits in a MTB fork with clearance, I’d just try it.

Just sand paper a bit of the arch away

The tyre might clear the arch on the lowers, it doesn’t mean it’ll clear the fork crown when compressed 😉

How old are they?

I’ve read somewhere pre 2012 (IIRC) 32’s could run 650b okay, before they ‘remodelled’ the brace.

Just give it a go. No harm in trying.

Yes they can. A mate of mine was a world cup mechanic and just changed the lowers when he went 650b from 26 on some 34’s. The rest stays the same only the lowers change.

I just run 650 wheels in a 26 fork. I never get near bottoming them out so just dont worry about it.