How to make a master of elements?

[Nettlekid]

I know there are many Prestige Classes and abilities catered to specializing in one element, like Elemental Savant. You choose one element, and master it. But how might one go about creating a master of elemental energy? Basically the Avatar. Air, Earth, Fire, and Water at your command? I suspect something Druidic is required, but I don't know what would be best. It would also be cool (if a little suboptimal) if you weren't using all the elements at once, but instead switched between them as need dictated. But using them all at once is cool too.

[ArcturusV]

Well... Shugenja is out because you have to bar an element. Otherwise it would be a good fit, as you get three out of four. If you could talk a DM into allowing a variant where you don't get a bonus spell of your elemental school per level, and retain access to all elements, that would be it.

Cleric with the appropriate Domains, and enough dips to get them all, might be another way to go for it.

[Chaosvii7]

You could invest in the Energy Substitution Metamagic Feat from Complete Arcane - it has a +0 Spell Level Adjustment to change the element of the spell. Archmagi get a similar ability, but it costs a spell slot - forever, but it lets you change it to any of them at-will.

If you wanted to do the Shugenja route, you could really press your luck and take Leadership for two Shugenjas - That way you can split the element thing up between the two of them. You could also make a sizeable "student-master" or "sister spellcasters" backstory for it.

[Urpriest]

Druid could work at high enough level...take the Elemental Companion ACF, and turn the usual saw about bears into being an Elemental with a pet Elemental who summons Elementals.