I believe it depends what character you are. But you can get +3 from both weapons if you dual wield (barbarian). Also +3 for a helm on tree skills, however I have seen helms which gave +3 to a specific skill as well as +2 to all skills, so that would be +5 from a helm. So overall +31 from equipment and 20 from hard points gives a max of level 51. Then +2 from a skill shrine and +1 from BC to give level 54 total.
Can't believe I forgot about +1 from the belt, oops. Didn't realize you could get +6 from a helm, but then again I don't pick up magical barbarian helms so it's not too surprising either.
Or course that's for a barbarian. It begs the question how high can the other classes get without BO and duel wielding... :scratchchin: