We’ve been trying to get Hawaiian support into the iPhone for a while now. A colleague just stopped by with his (I am still sans-iPhone) and showed me this screen! This is in Settings -> International -> Regions. When selected all of the date and time string in your iPhone will be displayed in Hawaiian, and in the right order, i.e., Po‘alima, 16 Ianuali, 2009.
There is no Hawaiian keyboard yet, but I’m hoping it will magically appear in a future update. Gotta love Apple!