There are a few providers available on Maui, but not many, and timing is important as you never know who will be there when you are. Most of them advertise on BP. Some on EROS. Some of them have decent reviews here on TER, and a couple other sites. (Paige, Angel, Bliss, and Sugar come to mind.--no first hand info, just names that I know have reviews here) Search TER reviews for "Hawaiian Islands." You can search under those names and also try searching, putting "Maui" in the location box. If you are looking on BP, be sure to research what you find there, checking pics and phone numbers etc. On Maui as anywhere else, BP is loaded with scams and fakes. There are several massage/tantra ladies available on Maui also.  
   
Providers from Oahu and the mainland do tour, so you never know who is going to be there when you are. Keep watching the TER "other cities" ad board, EROS, and BP.  
   
Depending on your budget, and schedule, you could travel to Oahu for a day or two and your options get a lot bigger. A lot more well reviewed indy providers are on Oahu (April, Alivia, Misty, Nikki, Deejay, Sabrina, and others, as well as the occasional visiting ladies). There are also many AMPs on Oahu, if you are into that scene

Several of the Oahu ladies are available to travel to Maui if it is in your budget.
 
Good Luck  
Aloha