Once you become a deity, there are a whole extra set of bonuses you get. You could be epic level and a deity, or in theory be a deity and not epic level.
The deities do get rule alterations as they get powerful (for example, a 1 is not an auto miss on an attack). Those rules are defined in the deity book from wizards.
To the best of my knowledge, however, there is nothing ever that allows your base four attacks to increase. Haste, two weapons, AoOs and all can give you extra, but even the deities cannot get above that base four.