Online marketplace buy and sell for users. (simplified ebay) finn.no

I am searching for a good website programmer who can team up with me an build this website. It will be a website where people can register, and buy themselves a marketing place in form of a sales ad(list the used or new items they want to sell). Like a selling forum just much better looking. Then people can browse the listed items, contact the seller and make a deal them together. A very good site to compare with is www.finn.no. Its quite easy to set up. No special payment gateways. just regular card services. This can very well be based on a CMS system too if possible. Like prestashop, joomla etc. I can either offer a small payment for building the site or we can share the profits of the site over time(obviously this will be a long lasting teamup as the site will need updating and such over time) THE grand idea herehow to earn money is two ways. The users pay a small fee to list their items for say 60 days. AND marketing from adds. Listing of cars should b a little more expensive. The users will be able to list what ever they want really. =) Please feel free to ask me if the description is unclear! Also come with a proposal of royalties wanted for doing this!=)