As I promised when this new Dev4Press started last month, there will be plugin able to automatically upgrade Pro plugins the same way WordPress does for regular plugins. And this updater plugin is currently under development and will be released next week.
Plugin will be able to perform the update of only Pro plugins, because Free and Lite can already be updated by the WordPress updater. For new upgrade plugin to work, you need API Key (on the profile page on this website). And plugin can update itself also, and will be able to upgrade to beta and nightly builds (depending on your license for a plugin).