Originally Posted by veganbikes

Why?

I don't see any reason why you need a chain idler/tensioner for a thru-axle? Tons of sliding dropouts that also use thru-axles. All City Super Professional was an off the peg option, Otso is pretty easy to get and Paragon Machine works makes at least one sliding thru-axle dropout and I know there are others that just don't come to mind at this time.