One thing a lot of people forget now the dungeon finder is so ubiquitous: if you have a group that has faith in you, if you actually travel to the portal, you can enter it at *any* iLvl. I just did Bloodmaul Slag Mines heroic with a guild group, with two of us being freshly-dinged 100s, without having gained much gear nor done Proving Grounds. It was tough, I grant you (part of the reason for doing it was to see just how nasty it'd be, given we were raiders), but perfectly completable.
So if there's people out there with faith in you, you could just skip the Finder completely.