Bronze for 10, silver for 25, gold for 100? I had a notion that there used to be such badges, but I can't be sure.
There is already a silver badge for 10 comments that have been up-voted 5 times. It is a silver badge because it's not easy to get at least 5 up-votes on 10 different comments, and that can be classified as "longer term goal."
The equivalent bronze badge is Commentator.
There are no gold badges because comments are second class citizens; badges that would have the effect of increasing the number of comments (which is what I saw happening in some cases in some SE sites) would not have a good effect on an SE site, as questions and answers are the main focus. Between questions and answers, it's then the answers that have more importance.
This question has already been asked twice at MSO, look at the following:
This request has already been rejected twice, but it's still a good idea. I reckon if we had more support for this proposal, it might come into being.