What are good scene modeling agencies?

I am not sure what you mean by "scene." If you are referring to "scene" as in the whole "emo" look, that type of modeling falls under alternative and to my knowledge there aren't any modeling agencies that specialize in alternative models. Maybe some online ones. Alternative models tend to be freelance and find their own work and the more well known they become--usually through the internet--the more opportunities they are given.

This is a link to an eHow article about becoming an emo model:

http://www.ehow.com/how_4910212_become-emo-model.html