I'm currently riding my 1x1 w/ 29er studs so there's plenty of room for 650s. In fact I think the 1x1/Troll will shine even more w/ 650s. The 1x1 was designed for 26x2.7, which I think is bigger than any 650s currently offered, so it should feel completely normal.
my plan is to find a fork that let me use a front 650B wheel on a late 90s hardtail.. and not screw the handling.
As others have said, the 1x1 was practically made for 650b. That frame was designed to fit 26x2.1 tires (11.5" BB) up to 26x3" tires (13.0BB). Iirc, with 2.3" Neo's, there was lots of clearance in the fork and the frame and the BB ended up at 12.2".
I have some rigid forks designed for 650b wheels here - with or without canti studs.