Harvey Dahl, or so says Pete Prisco. Prisco likens Dahl to Conrad Dobler which is certainly high ... er .. praise. Or something.
Notably to this page though is not who makes the list but who doesn't, in other words and not too surprisingly, no Lions. Prisco's definition of 'mean' isn't dirty, but rather which players take every snap personally, which players make every matchup into a war. Three Steeler's make his top ten, along with former Steeler Joey Porter. The Titans and Cardinals are also well-represented. Some quotes from the player descriptions:"He is a violent player who never backs down ... He's a big hitter who always seems to take the big shot ... He has no regard for his body and none for those he plays against."
I'm pretty sure those are also the ways you describe champions, and also why the better teams in the league are well-represented on Prisco's list. Can the Lions find a couple of those guys? Who knows, but if they do they will be making a huge step from a team patching holes to a team that contends.