Following some discussions*, I've gone ahead and removed the bundled ruby-mode.el and inf-ruby.el from rinari, to minimise confusion about which files are actively maintained as part of rinari. (* https://github.com/eschulte/rinari/pull/14)
Rinari users should either use the versions of those libs in ELPA, or alternatively grab ruby-mode.el from SVN at http://svn.ruby-lang.org/repos/ruby/trunk/misc/, and grab nonsequitur's inf-ruby.el from git at https://github.com/nonsequitur/inf-ruby.
Cheers,
-Steve