Gquickdrop is a project mainly written in Python, it's free.
Nautilus Context Menu Integration for sharing files via Dropbox
In Development
This is a Nautilus Extension to replace file sharing functionality that left with Facebook's Acquisition of Drop.io in quickly sharing files.
Right now only works from command line, but eventually will allow user to right-click on file in Nautilus, click 'Share with Dropbox' and immediately get the Public URL of the file.