The thrust cylinder fits flush to the outer end of the gearcase before it is lifted - so hard to locate an intermediary there. It is quite large, carries the radial bearing and was probably designed to take side thrust when the clutches used to be cable pulled.
If there is enough demand Oberon say they will machine pistons!!
However The double banjo bolt is so tight to the frame i could not even get 1/12th turn on it - so not possible to tighten it up
A new feed and bleed hose with a 90 degree double barb banjo to connect to the cylinder in the current position would work. But would add to the expense so that it might be cheaper to get the Brembo radial cylinders anyway.
Thinking about a 2 port cylinder as originally fitted Oberon said that as the bleed drilling is not absolutely perpendicular it would be unlikely to be fluid tight if it was drilled and tapped for the bleed hose. BUT if i can find an engineer to tap the thread and then spot face that surface it could work