Well we have a official statement of Rimowa:
Rimowa will not support the plans to reduce the standard size of 55x40x20cm and neither have we provided such a recommendation to IATA or any airline company.
Furthermore they say that there is no standardised guideline for carry-on luggage in the past despite previous recommendations from IATA. Airlines are still able (in the end) to decide for themselves which dimensions they permit.
Well this says it all, in my opinion it is the whole British Airways debacle with the 56x45x25cm carry on that will not be going in the new dreamliners of Boeing. Case closed.
Also a official statement from Lufthansa themselves: They signed the agreement that IATA search for a solution for recommended worldwide cabin baggage. They don't say anything about a 55x35x20cm. Also it is stupid to think that Lufthansa is going with this because they have a special Rimowa collection in Size 55x40x23cm for cabin.