You seem to have the impression that the architecture of a kernel doesn't matter for the apps you want to run on it. "Just plug in a subsystem". It simply doesn't work that way. What you are suggesting is taking a Harley Davidson motor cycle and a Ferrari and swap the engines. "Hey, they're just engines, right?". Although you could maybe make it work, the end result will be rather disappointing.
Gé van Geldorp.