Joomla Custom Extension

I am looking for a freelancer with a proven track record of creating Joomla extensions. The extension will be used on a live site with a view to potentially releasing the extension free to the Joomla community. Extension Requirements Must be 1.5/1.6/1.7 ready. Use of Mootools or JS, must use supported versions by Joomla. Must employ true MVC architecture so that the component and any modules can be over ridden at the template level. Could be built on Nooku framework. No embedded css, but all be separate files. Code comments. Extension Function This extension is a paid for support ticket and project management tool. Users purchase a subscription for ticket support based on X number of hours per subscription. Tickets are timed so that when a tech access the ticket any used time is then deducted from the pre-purchased support time. Tickets should allow a WYSIWYG editor, sing the default editor set in Joomla. Tickets should allow users/admins to include attachments and links. Tickets can be closed/opened by client / admin. The whole ticket system is a closed system, so that only the user and admin can access it and not viewed by other registered ticket users. For the project management side, access to it's functionality would be limited until a user has logged in via com_user and should allow link in with com_k2_user too. The project management side will include milestones, calendar, knowledge base, quote and invoice system, allow attachments, accept payments with Paypal as default via plugin with ability to create further plugins to extend the payments gateway. In all case, any links to content must include Joomla Articles, K2 Items or ZOO compatible content. This is just an initial over view of the project, if you can show examples of previous complex extension development then please make contact and we can provide a full design brief. We would be happy to here any suggestions.