What are the real life counterparts of the anime studios mentioned in episode 12 of Shirobako? In episode 12 of Shirobako, five major animation studios were listed:


  
  
  
  スタジオカナン (Studio Canaan)
  barmedéa
  武蔵野アニメーション (Musashino Animation)
  The born
  G.I.STAFF
  


I'm pretty sure "G.I.STAFF" is "J.C.STAFF". 

What are the real-life counterparts of the other studios?
Partial answer - I'm not sure about Studio Canaan.


G.I. Staff → Production I.G (the "G" and "I" on the in-show logo are lifted directly from the actual logo), possibly with an admixture of J.C.Staff
Barmedéa → Diomedéa (formerly known as Studio Barcelona; the logos are similar)
The Born → probably Bones (the logos don't really match, but the president of The Born [Inami Masahiko] looks like the president of Bones [Minami Masahiko] - comparison picture courtesy /u/TheVict on reddit)
I doubt that Musashino Animation, being the focus of the show, is a parody of any existing studio. If it were, the obvious choice would be P.A. Works (which is the company producing Shirobako), but P.A. Works doesn't really map onto Musashino Animation well. P.A. Works is a lot more successful, for one.