http://www.interrobangstudios.com/potluck/index.php?strip_id=1487
If you like the "Mega-crossover in an unlikely Scenario" trope and are familiar with the term
"Mary Sue" You will LOVE the above link, which links to the second half (and most awesome half) of a group that fits the "Modern League" description. It's amazing.
Anyhoo, here's my take:
The group has to form in Response to Something, and that something sort of shifts the focus of the group. Earlier in the thread there was an example where the mission was to steal important documents and I think that having a clear goal in mind when building the team is a great way to go. I also really like the idea that Project Mayhem is an expanding terrorist anarchist group that has to be dealt with, because that wasn't really dealt with in the movie (I should read the book at some point). So here is my Anti-Mayhem LoXG:
Tyler Durden - Probably the last actual recruit to the team, but obviously the first that comes to mind. He has knowledge about the Project that is necessary to take them down
Echo - From Dollhouse, basically just good at everything, but also has a bit of Jekyll in this version. Her mind has been tampered with quite a bit, so although at the best of times she can call upon her false memories to give her experience and skills at almost anything she needs, sometimes one of her personalities will become dominant and cause problems.
Angus MacGuyver - Because I just love MacGuyver. Though he might not be a good fit with the other, more violent team members, an updated Angus that knows Physical AND Computer engineering would be just unstoppable.
Jason Bourne - I only saw the first one, in which his amnesia and excellent ability to murder people made him very Wolverine-y
Sherlock Holmes (BBC modern version) - Sherlock is probably here very reluctantly fulfilling his brothers end of a bargain with some US Officials. This will have to take place either before he meets Watson and the series proper begins, or after Season 2 begins when we find out that he's still alive.
Finally, Project Mayhem needs a face, someone for our heroes to defeat at the end who, for the lack of him, the Project can't function. Tyler Durden invented Mayhem and he can't hold this position, so who could it be? My suggestion: V from V for Vendetta fame. He survived the events of his film, somehow, and has discovered the ideal vehicle for causing people to rise against their oppressive governments in Project Mayhem. Given all that we know about the American Government, he can probably give a really convincing speech at the end about how America deserves what its getting and is a nation of hypocrites.