Seeking a template with the same basic features as dropbox

Hi seeking a template that offers the same features with the likes of Dropbox.
Needs to:
Upload and store files in
Allow viewing
Allow secure guest log in
Secure guest upload
Allow for other plugins which can be networked with these alotted files
It goes on

This isn’t the type of thing you will find as a theme/template on Themeforest.

There are some file storage/sharing scripts etc. on CodeCanyon but it’s not quite the same thing.

Just as an FYI if you plan to run a platform like that which handles extensive storage of other peoples’ data and files, then you need to invest thousands of $ in hosting, maintenance and security, and using a stock site may be risky