Chris is going to be in MvC3? That's awesome. As for you saying it's too far stretched, the game where he appears in this time is just for fun and to mix characters from different games. These are not canonical games so why would it matter? Anyway, for other such games: Jill Valentine appeared in MvC2 (having zombies, crows, cerberi and the Tyrant as a backup) and Frank West (though not RE character but similar) appeared in Tatsunoko vs. Capcom. Also, Bruce McGivern and Fong Ling from Dead Aim appeared in an RPG that had some fighting game-ish stuff in it (Namco X Capcom). The game also featured Regina from Dino Crisis.

For other such stuff, here's a link to a thread I made on these forums:
http://www.residentevilforums.net/resident-evil-related-f8/resident-evil-fighting-game-characters-mugen-t1863.htm?highlight=fighting
There seems to be some really dedicated fans that want RE characters in a fighting game, dedicated enough to make their own characters

Yeah, the games are just for fun. It's not like it means that in the RE universe, Chris fights the Hulk. They are extremely good sellers.

I like these kinds of games...they let your imagination run wild

Nah, the proportions would be weird. But Superman did fight Scorpion from Mortal Kombat in MK vs DC. As for it being ridiculous, I can't believe any gamer would be so put off by it. Gamers thrive on ridiculousness. The best games in the world are downright ridiculous when all is said and done.

I think those games are the shameless whoring out of well established and well loved characters to make a quick buck. Never played one.... Never will.

Nah, that's too much thinking into it. To me it's just nice to see what they come up as characters in their fighting games. SNK has incorporated their characters in almost all of their main titles (KoF, AoF, Fatal Fury, Ikari Warriors, Metal Slug, Samurai Shodown...)

If it has good gameplay, I'll play it.

Whether any of you like it or not, many many people do. Which is why they are made. I don't know who came up with MvC, but it sells well. If you don't like it, don't play it. Not much else to say about it.