suggest a plugin (theme)

Hello everyone, am trying to create a community site which would allow two types of registration (author and sponsors). I need to allow the authors to post their ideas/project in the front end with photo, video attachments and the details of their ideas and category selection.

sponsors on the other hand, views the idea, likes it and could also interact the author. (Some how it follows the same model as classified plugins except that ideas are posted and not items)