After Compass started selling the 2.2" Rat Trap Pass tires I've been thinking that 26" is ideal. I started to envy Ms Cools lavender 26" Polyvalent after watching Henrywildeberry's youtube video channel. Here's a fantastic bike wheel and tire visual calculator showing why this set-up is better than the alternatives, by which I mean large-diameter, lightweight, plush, low-pressure tubeless, and fast.
https://bikecounterculture.com/2017/...er-calculator/
This tire and wheel combo is the same diameter as a 650b x 42mm, same as 700c x 23mm. I'm inclined to buy a Surly Midnight Special frame and run 26 x 2.2 for road, and then swap out the wheels for big-nobby 650b x 2.2 which would raise the bottom bracket and turn it into a drop-bar mountain bike.
Ms Cools Polyvalent: