Speaking for myself on the specific points you've raised: We're a django shop, but being a rails dev doesn't rule anyone out. A demonstrated record of shipping product and solving hard problems, regardless of language, is generally better than a lot of buzzwords that happen to be on point with the tech I'm working with to day. That candidate will probably get a phone screen, at least. A list of job responsibilities or technologies on a resume won't get you an interview if that tech isn't a good match for what I care about today.
But that's rails... ruby is a pretty strong language, and it's a much closer map to python than other options. As for your other languages...
Someone who's spent their life in PHP with no experience outside that language? At this point, I'd probably pass on that resume. The problems I deal with require a breadth of experience in deeper software engineering-y topics: networking, storage, maintainability... my assumption would be that you haven't been given hard enough problems that require you to get outside of the PHP box, if that's all you've ever done.
Similarly Java vs. Scala. I see a lots of J2EE resumes, and my experience with interviewing those folks is they may understand the J2EE/Hibernate/SOA/webapp stack, but when it comes to non-webapp problems, they're lost. I'd be more likely to talk to someone who has Java, C and Python experience, but no Scala, than someone who's got a broad Java base but has never branched out of that particular language. Scala experience, whether or not immediately relevant, is more likely to be correlated to be harder problems, self-development and exploration -- at the very least, that someone is trying to keep up with industry trends.
Maybe my J2EE and PHP judgments aren't fair; but they're heuristics developed over some time.