voice acting category

The credits for voice work gets listed in the actor's acting credits...do you mean pull those out and list them as a separate category (director, actor, writer, voice)?  Kristen Bell has done a lot of voice work.  See how nicely it fits in to her filmography (take note that the credits will have a "(voice)" attribute.

I'm not sure how that would aid in searching, but one downside is, if you're an actor and you've done 3 films, then do voice work for five more, your page will indicate "voice" first over "actor," and I can tell you right now, those folks affected this way won't be happy.  I think it's still considered very much an acting skill