a) yes that would be cool. There's already a lot of other T/S adapters for various lenses to Mirrorless systems (i've also got a few for MF lenses to my EF bodies)
b) But 'af passthrough' wouldn't work. AF works by looking at the relative phase-differences of the lightwaves coming through the lens. as far as I know, if the lightwaves aren't coming in at the right angle, AF would struggle (if you've ever used a tilt or shift lens, or lensbaby, you'll know it messes up the light-metering, same deal). But using contrast-detect in live-view works (for light metering at least). so maybe it might work for AF too (the contrast-detect af, not the phase-on-sensor). Still, I don't know what would be the point of a t/s lens with af...
At least being able to pass the aperture-closing signals through would be good, then any EF lens would be a t/s lens (no point on ef-s lenses). I was thinking that might be difficult to keep constant-rotation in the adapter, the wire links can't go around forever. But then I realised that normal TSE lenses so that anyway, so there's probably a way around it...
