It's definitely possible. I've seen and experienced what great mods are capable of (nearly anything), and it's really a simple request, compared to a lot of other things people do to games these days.
It just requires someone more skilled and imaginative than most of the zombie modders I've seen for the game. I'm not saying those people are unskilled, at all, don't get me wrong, but zombies should act like they do in The Walking Dead (the TV series).
We want zombies that not only flail at you, but that will bite you. Maybe even grab onto hard enough that you would have to pistol whip or shove them off of you. That, of course, requires entirely new mechanics, and that's not easy job.
I wish I could be the one to do it. I currently have plans to take online classes to do such a specific thing, but for now I'm just an annoyed mod-user and forumer. :/
Good luck with the search!