Share + Sync - Service

Hey Everyone, I need a website that should work like dropbox, mozy..etc. Users will have a certain amount of web storage space and also need you to develop the desktop app so the user's storage can be synchronized with 1 or several of his local machines. The desktop appliction should be compatible with Mac and PC and work with regular system folders. An IPAD and iPhone app should be available too that sync across all platforms and updates changes automatically. The site has 2 levels of users, free trial users and paying users, the only difference is the amount of storage they will have. Paying users have chance to set policies of files. I would like to have the main dropbox features, like file synching, the referal program where the users get a little more space for each user they refer successfully or are if they are referred. It is very important too, for the users to be able to share certain files with other specific users. I will also need a comprehensive user admin, where I can see every user, the space they are using and their files. I should be able to upgrade them and downgrade them. Send them a collective email or a private message If you have developed a similar site, please refer me to it. I will provide brand PSDs. In general, I am looking for someone who is well familiarized with the service and is confident they are confident to recreate the features described above for a reasonable budget and timeframe. Note: Please be very specific in your proposal, as to the technologies you intend to use and also about the budget, it would be helpful if you break it in parts, so I can decide what features to choose and which to leave out. And your personal comments and suggestions. Regards Gaurav