A Joomla/K2 extension built

I want my own extension, exclusive to myself, that easily uploads & installs same as other extensions in Joomla Extension Directory. Must be built from the ground up so i can call it my own! He who creates it for me must not share the extension in any way, shape or form. Must provide all files related to the creation of this extension. The Extension is to allow different k2 users to private message (PM) one another, a (PM - message user) or similar icon needs to appear next to their avatar or username - common sense applies. With some kind of anti-spam in the form , Fields need to be: NAME: EMAIL: MESSAGE: UPLOAD FILE: The extension then notifies the sender & receiver through an email. A built in 'INBOX' inside the account page is not necessary but would be considered a bonus! Must be compatible with joomla 3.0 especially & possibly 2.5. Must be a Joomla Expert with previous example of extensions/creations in Joomla. Please read post clearly & consider if you can accomplish my goal before making an offer to me, ensuring it can work! Thankyou