Exactly, that's the problem. Catch 22.
You become an authority because a stackload of people use your site as a resource. You cannot do it by content alone. So you need to start with a reciprocal linking campaign to get your initial traffic and hope the thing takes off from there.
Ideally, have some unique content. That's what we did. We're the only website on the internet offering what we offer in the sector that we are in. It's a gimmick, and it works. I see in the logs every day two or three new sites that have linked to us who's existence I didn't even know of. Of course, the majority of them are low PR2's and PR3's (the odd 4 and 5 though).
But they're coming in quantity, and I'm sure the quality will follow.