In early August of 2008, less than 1% of the US knew the name Sarah Palin. Name recognition is meaningless at this stage of the game.
Republicans have never chosen as their nominee (at least not in many many years) someone who couldn’t be seen as the “top” Republican running.
Sarah Palin got instantly famous by getting picked for VP.
That won’t happen for anybody on this list before the Presidential nominee is picked.
Certainly somebody with low name recognition could come on to the scene.
That said, where has such a person been over the last two years while Obama and the Democrats in Congress have been destroying our country?
Potential candidates such as Palin and Bachmann have been out front putting their necks on the line. That's why they have high name recognition. Meanwhile, the low name recognition types have been hiding from the fight.
Tea Party types and Republicans won't forget that come primary time.