The first question the rest of the board asked me was "Well, are we going to have trouble hiring?" To which, I truthfully replied "No." The interesting part about non-popular languages, is that you're going to have fewer unqualified candidates. (And yes, in my local market, there are still a lot of perl programmers, maybe not as many as Ruby programmers, but the average perl programmer I come into contact with has more years of experience than the average Ruby programmer I come into contact with.)
I think the argument "we can't hire people that know X" is nearly always the wrong one. Several years ago, when we looked to re-build core services for a product (replacing perl with Erlang, natch!) - we couldn't hire a person that knew Erlang to save our lives. So, we hired good developers in other languages and trained them. If you've got the right technology and the the right tools, you can always find the right people.