So apparently, they will be expanding the field in 2011 It's still kind of vague, but it looks like this is being done to turn the event into a four-game tourney for top teams, and will have eight guaranteed quarterfinal slots similar to the four guaranteed semifinal slots that other tourneys had.
I know that a lot of people think that these "aren't really tournaments if you're guaranteed to advance," but I think that this is an important step for Maui long term. There is always the lure of Hawaii, but I could see it becoming a second tier tournament 10 or 20 years down the line without this. The teams that have their pick of tournaments are increasingly leaning towards four game tourneys to get the extra game on the schedule. In the 8 team format, the team that plays Chaminade essentially loses two games off of their schedule. Calipari (yes, I know that it's Calapari) has expressed his distaste for this side effect of Maui. Since the end of the two in four rule, Maui is the only 8 team tourney that Duke has participated in.