I was at FOSDEM this year (2016) and there was a talk from the leader of LibreBoot.

Honestly, his talk on the state of the project was very bitter. He literally said that there is absolutely no hope that LibreBoot will ever be able to cope with ME, and that the fight is over since 2008.

As much as I would absolutely love to be able to run a free firmware, unless there is a major change/outsider in the hardware manufacturer world, it seems very unlikely that it will be possible on current x86 architectures.