Along the lines of something Turbofan said; The only significant discussion the FAA has engaged lately concerning crew rest is the need for a minimum 48 hour layover after very long range flights. If I understand correctly, these flights have two spare pilots and bunks for the crew onboard. I am sure there are circadian rhythm issues and other human factors concerns that need to be explored. I cannot begin to understand what makes this a more pressing safety issue than the schedules regional (and now some major) pilots are faced with all the time?