Re-build the back end administration system of our site

I'm looking to re-build the back end administration system, possibly using the Wordpress engine. The site is currently written in PHP with a mySQL DB. Our Site: [login to view URL] Some of the additional features I need on the system include: 1. Ad server (I'd like to use an Open Source tool such as "OpenX") 2. We will want to use the FlowPlayer and be be to continue using the existing system 3. Be able to post interstitials, etc 4. Migrate all comments and allow comment filtering 5. More Web 2.0 features such as (but not limited to): 1. Built in social networking such as Facebook's Open Connect, "like" features, auto-posting of videos to FB fan page, and Twitter page 2. Create a downloadable iPhone app for the videos; with a "send to a friend" feature 6. Auto-posting of games (from Mochi Ads) videos and other content (like what you've done on Basketball-HQ) 7. Automated email (like what you've done on Basketball-HQ) 8. Link Trade system (we have one already) 9. A Point System (we also have this already) 10. A "hot link" feature (we also have this already) 11. Ability to manage the categories and site structure easily ( 12. Some of the other built-in features you have on Basketball-HQ, like the site map, the auto-responder, the email newsletter signup, etc. 13. Administrative System/Engine Cloning: I have a "sister" site too, that's an NSFW site, using the same admin system. Whatever we build for [login to view URL]'s back-end system, I'd like to use for HexZoo. 14. System needs to be able to accommodate over 7,500 videos, 2,500 pictures, etc - see [login to view URL] for what we have. Basically take the existing site with all features and content and rebuild the backend plus add on the additional features as above. I would assume depending on programming that the whole system would need to be ported to a new platform.