I think Wolski and Schremp are the two candidates that come to my mind. Both have been projected top 10 pretty consistently all year, but both meet the profile of unquestionable skilled players that might play on the perimeter a bit too much for NHL scouts liking. This can scare scouts more than anything, and I think both may fall out of the top 10, with one dropping down to the late first. I don't think either will fall to the 2nd round, but I sure as heck didn't think O'Sullivan or Hudler would drop to the 2nd either. Of course, either could still go top 10 if a team likes them enough. Obviously it's a crap shoot this year as much as any after the top 2 picks.
I also think O'Neill fits the bill of possibly falling out of the 1st round, but historically, big d-men who skate well don't fall as much as skilled perimeter players. Something tells me several teams in the first round will like what they see in O'Neill enough to that he won't sit in the stands too long.