How does your level affect Quest Rewards?
It seems to. At least, this source seems to believe so.
It would make sense, too. Even in the last two Fallout games, the rewards were leveled.
It is, at least for the Main Quest.
When you fight enemies (specifically the Thalmor in Act 2 of the Main quest), at level 50+ (I'm at 62 when I fought them) they dropped Elven and Glass Armor. Enemies that wore heavy armor were dropping Ebony armor and ebony weapons.