I’ve been mulling over the axle fitting for this project half the morning I started off fixated on the idea of a single side clamped axle, but that would end up being a bit of a monster.
I’ve settled on the idea that you all you really need is to fix (Weld or laminate in depending on construction method) a tapped boss or of you like the whole stub axle itself, and it can all be held in place with a RH threaded pre-load bolt (pretty much what the lefty setup does) the fork needs to be a “Lefty” really not RH legged for the simple reason that a Lefty means that RH threaded axle fixings would be tightened in the direction of wheel rotation, if you do it as a “Righty” and you’ll be needing LH threaded fixings (bound to cause issues IMO) or to clamp everything, not perfect IMO…
Hubs wise I think you’ve actually got some options, you could track down and use a Lefty hub / axle, alternatively you could try:
-20 x 110 DH hub (pretty wide for this application though, hardly “Aero”)
-Space a 20 x 110 down to 20 x 100 (or narrower?) with some replacement end caps
-QR 15 x 100 hub – a 15mm axle might just work cantilevered for road only use?
-Hope Pro 2 or similar hub that allows different axle configurations, kitted out with RH 20mm LH 15 bearings and a stepped / tapered axle and end caps made up to suit…