Smoker's final rank should be Vice Admiral, so my guess is that he's already achieved it and will be declining promotions to Admiral for the rest of the series. Of course it's also possible that he's still a Rear Admiral with a promotion yet to come, but I find that to be less likely due to the length of the timeskip.
Oh guess I forgot about that.. Commodore was the obese guy that wanted dragon bones in the anime, right?
Actually he was an East Blue admiral, which is the equivalent of a Grand Line Commodore, so you're half right (Oda said that the ranks of the marines in the four blues are about 3 ranks higher than at HQ in the Grand Line). But he was just a filler character, anyway.