We highly recommend using ruby-install to build Rubinius instead of rbenv or RVM. ruby-install does a good job of making sure the prereqs are met, including getting a build ruby. See also Getting Rubinius.
We intend to eventually provide packages and binaries for other Unix/Linux systems. If you are interested in helping us get a Concourse CI build pipeline going, or in building binaries for a particular OS and sharing them, join us in the Rubinius Gitter channel.