If the area you're looking at is that flooded, you might be better off just settling for a catchy name, even if it isn't full of keywords... and hope that you have good enough to content to compete. I don't think anyone has ever failed because of not having keywords in the domain. Using the apartment finder example again, if you really want to have keywords in the URL, you can always go the example.com/apartment-finder or apartment-finder.example.com routes. But I'd just come up with something simple and work on branding. Google seems to be doing okay, even without having search engine in the domain.