Mach has always been a very interesting project. It doesn't surprise me at all to see that they have this already, but at the same time I was not aware of it so thank you. This also more or less proves that that may well be an avenue worth pursuing.

I learned of the idea from some paper or other of Barrelfish, which is a research OS based on seL4. Barrelfish is underrated! Aside from its takes on a kernel architecture, it also has interesting nuggets on other aspects of OS design, such as using declarative techniques for device management.