The brands you mentioned, quality they may be, but it's highly unlikely that the quality is actually any higher than say, DT Swiss or Hope. Probably higher than novatec. Higher than Shimano? Depends on the line. Higher than Sram? Most definitely.
Your assumptions are incorrect. Phil Wood uses heat treated SS in there hub axles. All the parts are over engineered. If you need to replace a bearing two 5mm hex wrenches are all you need. There hubs are not the lightest either.
Sme goes with the Paul Clampers. They seem to use the same principle as Avid BB7's
Paul uses the one piston system like Avid and several others do. You can make a stronger brake with one piston. Paul did not stop there. There is no perceptible play. There is no flex in them. Paul did not make the mistake like Avid did and put plastic pad adjusters in there calipers. Some tandem riders going down a mountain lost the ability to brake because of the plastic in there brakes. The Klamper is not the lightest mechanical disk brake caliper. It is the best stopping mechanical disk brake out there. Did I mention that the Paul Klamper has bigger balls. Yes the Paul Klampers balls are larger than anybody else's ball bearings.