I'm sure there will be plenty of leadership opportunities such as leading a study group, but the ones that would really be impressive to a recruiter are the ones that I imagine would require the biggest commitment. For instance, if I was a recruiter and I saw that someone was the Treasurer of the [fill in the blank] Club, I would think, "Okay, this person made a half-a$$ed attempt at getting involved, because really, who cares about being the Treasurer of a club. Collecting $5 club dues once per year isn't all that complicated."
But if someone were the President of a club and was necessarily involved in arranging all sorts of activities, that would impress me.
So I guess it's the real "premium" leadership positions I'm thinking about.
Well, I'm skeptical that recruiters will actually care that much about the actual brand of leadership positions during B-school. Sure, if you want to go into Consulting, then join the consulting club. But does that mean that McK will only hire the club's president? I don't think so. Once you've made it to the interview, you should have some leadership experiences to talk about, some group work experiences, etc. But not necessarily the top position.
I also think pre-MBA experience (at least pre-MBA leadership experience) will be weighed much more heavily than any club leadership you can do. I call this the "pre-season vs. regular". Which would you rather win? A pre-season game (=school leadership) or a regular season event (= work leadership)? Which one's tougher?
Furthermore, I think that being a section president is not only about leadership but also about willingness to commit time to that particular activity instead of to another. B-school is a 2 year exercise in time management and compromising.
The only case where I see that an extra during B-school will have a very high impact on recruiting would be if you were involved (and got a nice place) at a multi-school competition of some kind. But that's not necessarily about leadership.
My $2 x 10^-2.