One fan of Team Fortress 2 and the classic NES Mega Man games has mashed the two up: Can Scout Man possibly take on the likes of Heavy Man and Demo Man?
Oh, TF2 mashups, do you ever get old? I submit that you do not - this particular project is the work of DeviantART user AgentMidnight, who is busy reimagining Team Fortress 2 in the style of the old NES Mega Man games. At the moment, he has some sprite art and animation up in his DeviantART gallery, as well as the character select screen you see here.
There's no word on if AgentMidnight ever plans on perhaps turning this into a full fan-made project, but the little that is there is actually pretty cool. I'm a particular fan of Spy Man's cloaking animation, myself.
Of course, any classic Mega Man fan worth their salt is going to look at the image you see here and immediately start trying to figure out the best order in which to fight the bosses. We all know that Pyro Man is going to be powerful against Spy Man, and Spy Man in turn beats Sniper Man, who is strong against Heavy Man, but that's where I get stumped. I guess Demo Man would be Engie Man's weakness, though - it only makes sense.
I know I'd play this game, for sure. I bet fighting through Saxton Hale's castle would be a total pain in the ass, though.