I believe one of the patent holders is Bell and they brought the system up to a technology demonstrator. Clearly it ran into issues, likely those mentioned above. As for servicing and powering, don't they operate rotor ice protection systems (RIPS) where there must be power and the ability to service the components?
I'm certain with at least the military application if it could be done it would have but then again DoD contractors tend to move at a snails pace when it comes to new technology. I'm just wondering with all that is new in technology why a system couldn't be made viable? Let me qualify myself here, I am not a pilot or engineer just someone who thinks too much sometimes.... lol