none is the answer,
I have done a lot of stuff regarding comics since that was initialy my ultimate dream and since I was drawing comics since the age of 7.
The once that get hired by DC or what ever other comic publisher are the once that are ultra talented, they don't need any models most of them would put you all to shame when it comes down to the initial knowlage of Anatomy.
If you need to have somebody to model for you, you are obviously not ready to draw (pencil) action comics.