web based worldwide travel site

the basics: much like an internet dating site, the desired website needs to be a very clean looking and functional database driven site. See airbnb.com. That style and functionality is what I'm looking for. Ease of administration is a must. The site will allow first time visitors to browse the site, join the site via username and password with email verification, then post profiles of themselves (complete with text description, photos, etc) and rate other users across multiple criteria. The site will be set up for automatic billing of users via credit card, paypal, wire transfer or goldmoney.com. The site needs to have an internal messaging component. The site needs to have a calendar function enabled for each user to share their availability. The site needs to be searchable across multiple criteria by users. It must be written on a common, widely-available platform for ease of modification. I've looked into droopal and like it, but submit your recommendations. Again, functionality and style very much similar to airbnb.com.