Pistons are stupid small, at 15/16mm. Could be fine if they had their own lever out with a small enough MC to suit, but if you're supposed to use someone else's lever, those are going to be wimpy.@Udi why not pay a visit to this producer of 3d printed caliper based in NZ?
The alloy they use has half the yield strength of good old 7075 but they can put the material where it's needed.
It might just not be cheap...