I doubt kishimoto will make Naruto go through another chuunin exam - sure rank doesnt always have a direct relation to strength (not for chuunin at least) but think of the level difference between naruto and the other would be chuunin nominees. Kabuto is an exception because he doesnt go through w/ the exam in order to hide his strength. Any "normal" ninja however will actually try to go up in rank. If Naruto can fight Akatsuki and has gone through training from Jiraiya its rather pointless and unrealistic to make him go against typical genin class ninjas. I feel that Tsunade will promote him sometime or other in the manga.... but I also think that a chuunin exam filler arc is very possible.