Bought it from a local ice cream shop; they gave us a great deal because it was a not for profit, plus free program ad. We couldn't beat the price making it ourselves.
Another truly wonderful thing that is typically Hawaiian, is a coconut milk based custard. The very best quality comes from mixing equal parts of coconut milk, dark brown sugar and egg yolks, then baking like any egg custard. It is so rich that you have to have a special plating plan for very small servings, but out of this world and easy to do ahead. The quality is perfectly acceptable made with some whole eggs, so long as you strain out any tendrils from the whites.
How many folks are you serving?