Custom Group Buying Website

I'm putting together a website that is similar to the group buying deal websites out there, like Groupon and LivingSocial. Looking for professional web developers who have had prior experience in building websites such as these. You should know how a group buying system works inside-out and be confident in creating a professional-level product. I would like several custom features on the site, for example a virtual cash rewards system, a lucky draw system, or an easy way to email daily deals, so you should be able to implement them if you are installing a packaged software. The site should also be easily adaptable should I need to make changes in the future. Development time should be fast and painless. Aside from the usual features, the website should be secure and protect user data. Most importantly, it should be SEO-friendly. Please send me links to your resume or previous works by PM. You might be required to show some demos of your own custom work. Logo and a rough PSD of color scheme/layout will be provided, as will a full list of required features. Best regards and good lucking bidding.