Here I have two suggestions on tag specific badges,
To get tag specific badges you should get 400 or 1000 upvote on a specific tag. You can see how much score you did on a tag when you click on a tag, at stats panel.
I think it would be great if we can see our score at our profile, or can we see them somewhere else ?
Accepted answers seems like have no effect on users score on a tag. In my opinion they should have a score point.
What do you think ?