Tamba Hali is one of them. Other players that come to mind are Terrell Suggs, Michael Johnson, Trevor Scott, and perhaps Brian Orakpo or Andre Carter.
The Giants have also been experimenting with Mathias Kiwanuka at SLB in nickel packages.
It really depends on what service you are using as a league management tool. MFL tends to be more quickly updated than other LM services such as Yahoo! or ESPN and is therefore a little harder to grab players that are "mis-classified."
Jason Taylor is supposed to be an OLB in new york but is classified as a DE in ESPN ... any word on his role there?
Also intriguing was Robert Ayers moving into Dummerville's starting spot in Denver at OLB. He's also classified as a DE. What's the word on him? Close to Dummerville type production? I have him scheduled as a late round pick up in my draft as DL is often an after thought to most people in my league.
Taylor will just be a nickel-rusher for the Jets this season and doesn't excite me at all fantasy-wise.
I like Ayers potential. But I don't personally see Dumervil-type numbers. Elvis was a special player and not many players in the league can put up the type of numbers he did without much surrounding talent. I see Ayers generating 7 or so sacks. He's a talented player, but he doesn't have anyone else to help rush the passer and his stats and performance may suffer accordingly.
With the additions of Matt Roth, Scott Fujita, and Chris Gocong, Bowens has slid inside to the SILB position next to D'Qwell Jackson (or Eric Barton for the time being). He's a starter and will provide very good tackle numbers for a defensive lineman. If he's still classified as a DL, I would grab him.