Crowdfunded event site

Essentially I need a website built that is similar in function to many of the other crowdfunded sites out there (IE kickstarter and indiegogo) but this site is strictly for events, concerts,parties, and conventions. The user needs to be able to put the details of his event in and then lay out a series of incrementally increasing bonuses for contributing money to the event. The contributors will enter their payment info when they pledge the money to the event, but the money is not charged or released to the event poster until it is fully funded. Essentially, the reason for the site is so that people can organize large events without risking any of their own money. Also the users of the site must have individual profiles and events that are posted in their geographic area need to be made visible to them as they are posted. They would also receive notices as their friends pledge to events. The site needs to be web 2.0 and utterly polished. It is imperative that the site looks very professional. We need a functional site built from the ground up. [login to view URL] Developer must be fluent in English.