Check these two builds out: Resto (0/21/55) and Ele (55/21/0).
Dual-wielding caster builds.
I think I may just resuscitate my shammy.
EDIT: Hrm, not so much. Looks like every caster weapon in the game is Main Hand, not One Hand or Off Hand. A shame, that could have been a very impressive boon to the oft-shorted Elemental build. Though I'll admit a Resto pimping Earthliving and Flametongue on each weapon might have been a tad powerful.