We used a company called Elegance Transportation for our
Disney Cruise transfers.(
http://www.elegancetransportation.com/hummer.html )We also were a party of 15. I have used Happy Limo once before. When I went to book them again I just wasn't happy with the service I was getting on the phone. This company has plenty of big limos and there prices are very good. I did a lot amount of research and they had the best price I could find. They showed up on time, their vehicles were nice and clean, and the drivers were respectful. We reserved the Excursion and got up graded to an Esclade. For the trip back to the airport we got up graded to a Hummer. Over all the service was good I would use then again. There are hundreds of companies out there, but it seems like only a few get mentioned here.