Warning: Left 4 Dead 2 is a violent game with blood and zombies. Look away if that's something you don't want to see.
If you have a need to switch the in-game Left 4 Dead 2 player Francis for Krystal (and who doesn't?), there's a mod for that! Modder Ruby The Bat provides this free L4D2 mod that's based on the rig by Rhyfe2002.
- Francis is replaced with a Krystal model
- If playing as Francis, you see Krystal's hands
- New Krystal UI elements
Of course, you can have more than one Krystal on your team with this other Krystal mod. Edit: Actually, you can't have Francis and Rochelle on the same team, according to Dogman15, so only one Krystal per team it looks like.
Video of the mod by United4Games.