Yes, exactly. That's what I do when I interview people. I make it clear that this is something I am actively trying to solve (or maybe I've just recently solved it), and not just some academic exercise I'm doing that isn't productive.

I think that makes a huge difference. And in the end, I don't care what language you do it in or how you do it, so long as you solve the problem. If I write it in Ruby and you write it in Java, then if it works, I can hire you and your first job will be to port it over ;)

I moved to SF and I love it, but I understand not wanting to move around. I'm resisting moving away from SF for other opportunities...