Hi Emerson,
I'm confident you can do essentially what you are describing with the correct DMX folder structure and security role or user permissions. The drag and drop is possible with DMX WebDAV, but is more complex to setup.
You can keep it very simple if you go with the concept for the admins of browsing to a folder on the 'admins' workstation or network share to upload files to the appropriate DMX folder. You should use the Template view to keep the UI simple and clean.
If you haven't found someone already, I would be glad to work with you.
Rob Ralston, SilverBullet Technologies LLC, www.silverbullettech.com , rralston at silverbullettech dot com