Well... habermann24 (https://github.com/habermann24/libphonenumber-ruby) looks like he's started on a ruby port and he also has his phoney library which doesn't appear to use the same dataset and doesn't work properly for Australia.

I am planning on just using the Java version with JRuby - it will probably be faster than a pure ruby version anyway.

Not the answer you were looking for, but you could run the Java lib with JRuby, or use the JS lib with Ruby/V8 and "The Ruby Racer" (https://github.com/cowboyd/therubyracer)

Or python... I'm hacking together regexes for dealing with specific country formats in django right now... Is there a comparable python lib available?