It just seems to me that instead of bringing out another size rim, the simpler solution would be to make a wider tire for the existing 650C size. 650B was obsolete for a reason. It's right between two popular sizes and does nothing that the existing sizes can't. For instance, it would be simpler to make a wider tire for the 571 rim than to make a wide tire for the 584 - and make the rim too. Ah, but then they couldn't sell both to a gullible public.