Haven't played with these yet, but they do look interesting. Might have also to add support for the new IO blocks in my AVR simulator simavr[0] -- I still use the AVR a lot, since they have no pipeline and other fancy CPU optimization, they are 'cycle accurate' and are a lot closer to a PIO than most other more complex 32 bit CPUs..
Now that they ALSO have an equivalent to PIO it might even help with reaching faster IO speed when toggling pins.