Human like creatures touched by the elements. Could go many directions on the stats, restrict class to invoker, druid (yeah goodie druid), conjurer, warrior, and thief.

The really nifty thing is that you could give them all one or two inherents so that different genasi represent different elements.

Have ice/fire/air/earth/storm types. Could give them affinity bonus for invokers and conjies when dealing with their kindred element.