Event Registration Site

Hello, I am looking to build a online event registration site for a specific niche market. This would be similar to other popular online event registration sites such as [login to view URL], [login to view URL], or www.eventbrite.com. Essentially, I would set up a subpage site for them - [login to view URL] - and the system would be able to handle all the registration needs for them online including: capture of name, email, etc..., they could manage the databae themselves so they would need to have some admin ability, special needs for each event such as meal preferences, breakout sessions, only attend half day, etc... - payment processing ability so that we can process the payment or they can hook up their own paypal or whatever they use - and more.