It's funny that when I was first reading the title of your thread and your first post, I thought "I don't want this guy to trade for pierre" and the two subsequent posts both said to do that...they are not wrong, I just think that that easy solution is by far the most difficult to pull off.
Would YOU trade Juan Pierre? I wouldn't, because no matter what I wouldn't give up a guy who dominates one category the way Pierre can dominate steals. Perhaps I exaggeate (actually no, i AM exaggerating) but my point is that Pierre would be so expensive to acquire that you seriously hinder your chances at winning other categories.
Instead, go for CHEAP steals. Brian Roberts is a cheap steal guy and hasn't stolen a base (i believe) since two days after he stole 4 in one day, when he stole two. The dude still has wheels and will steal plenty, but right now market is low on him as he is not necessarily free from "flash in the pan" status after that huge game because he hasn't done too much since...but he will, so he's someone to look at.
Likewise is Carlos Lee. Did you know he stole 18 bases last year? Me neither! But he did, and he's been terrible so far so you can buy him REAL low...I was actually able to pluck him off the waiver wire which was incredible.
Johnny Damon is another option...30 SB's in Boston each year so far, why will that change? I don't like that he doesn't do so much else though, ESPECIALLY in the first half of a season.
Basically, what I like to do is get guys who contribute to all categories...Beltran obviously, but don't overlook Bobby Abreu, who is known to me and my roomate as "Poor-man's Beltran". I may not be a lock to win any one category every week, but I've got like an 85% chance to win them all, rather than mortgaging myself to a 50% chance to win homers/rbi but locking up the one category of steals.
If you ask me, this list of guys will help you more than targeting Juan Pierre because you don't have to decimate other areas of your team.
Alex Sanchez *
Dave Roberts *
* Sanchez and D. Roberts might be tough because some people realize that they ARE Juan Pierre...if not though, MUCH cheaper.
I think this is the path you should follow.
Rest in peace Mitch Hedberg. I name my fantasy team "Buoyancy of Citrus", in your honor.