Aye. It's neat and all.....
I recently started working a bit on some stuff for an Avatar d20 thing, but nothing's really finished yet. Feat and skill based; take the Airbender feat, you get access to the Airbending skill as a class skill and get 1 free rank in it, for example.....etc. With other feats for unusual or unique specialties, like the Lightning Redirection feat, a Healing Flow feat, a Metalbender feat for very experienced and talented earthbenders, etc.... Probably going to add a few other feats that just give general, minor boosts to a particular element and related skills/stats used by that type of elemental 'bender.
An Elemental Avatar template, a Master Avatar prestige class (3 levels, covers mixing of elements and mastering the avatar state), an Airbending Master PrC (5 levels), and equivalents to that for the other three elements. Expected for use and compatibility with both 3.x D&D and d20 Modern (or similar systems; it assumes the use of certain feats and skills that are found in both those games).
'Benders would probably advance in normal classes (likely aristocrat, expert, warrior, fighter, rogue, monk, and barbarian), taking the feats and spending skill points to use their elemental bending. Airbending skill for now I've got tied to Dexterity, Earthbending to Constitution, Firebending to Charisma, and Waterbending to Wisdom, as the key ability scores for those skills. Any really-dedicated 'benders will take Skill Focus in their 'bending skill, and later the prestige class relating to it (each of which requires a few appropriate skills and feats to enter, such as Iron Will, Earthbender, and Skill Focus (Earthbending) for the Earthbending Master prestige class).
