Ubuntu has a rails package already, and nobody uses it. It only serves to confuse new users. Trying to mix deb and gem just hasn't worked well so far.

Making a Rails.app for Mac is different though, because everything would be isolated in your .app, while a .deb would install the files to the system and track them in the package management database, so trying to modify them outside of apt-get/dpkg just b0rks everything.

Wouldn't you have to stage a coup against the Debian maintainers? Isn't Rubygems still deliberately broken there?