I think I agree with the proposal...

It would end hassles at templates, checkin, boarding, etc. Of course, teh plan would have to be phased in over the average life of a carry-on style suitcase (say, 5-10 years?).

Or perhaps a voluntary standard could be set that all airlines accept and luggage manufacturers are aware of, so that instead of advertising "allowed as carry-on by most airlines" the bag could have a statement, this luggage is in compliance with the ANSI (or ISO9000) standard as acceptable carry-on luggage for all airlines worldwide...