I can argue with Haskell but I would never argue with teh awesome that is Don Stewart.

Urbit runs on Linux right now - but you're right, it would be very cool to run directly on the hypervisor, and it's totally possible for a self-contained system like this one. Personally I think Haskell never should have tried to be a language for producing Unix system calls - the impedance mismatch between FP and imperative OS is just too great.