What rank does Edward Elric hold? Ed is a State Alchemist, but what's his rank within the military hierarchy?  Col. Mustang explicitly mentions a few times he's his 'superior officer', so he's a bit lower than that, but how does he compare to Maj. Armstrong or some of the staff Lieutenants?

Are State Alchemists commissioned at some rank (e.g. Capt.) a la physicians in the US military?
According to Maria Ross (episode 9, 3:42), all State Alchemists carry a military rank equivalent of Major.