Great news! rgedit was accepted into Sid as "gedit-r-plugin" (http://packages.debian.org/sid/gedit-r-plugin) thanks to Mateusz Kaduk. Thus, the users of Debian and its many derivatives (Ubuntu, Mint, Sidux, CrunchBang, etc.) will be able to simply "apt-get install gedit-r-plugin" (with the right repository enabled for now).
Thanks again, Mateusz.