Design consulting firms

After meeting with Dev Patnaik and Peter Mortensen last weekend, I realized that there are many more design/innovation consulting firms in the world than expected. Since managers probably want to know which firms they should work with when any consulting service is needed, I attempt to categorize them.
I used one axis to categorize design consulting firms: how much they emphasize business vs. how much they emphasize product design. Jump Associates and DesignWorks are far left at the “business,” Ziba Studio and Design Continuum are next, IDEO is in the middle, Gravity Tank is next, and then finally Frog design is far right at the “product design.”
Dev used three circles and categorized design consulting firms: design, business and culture. He included more players by forming a culture circle (e.g., Bruce Nussbaum and design research companies) and put more firms in the overlap areas. Advertising agencies are in the [design + business] overlap, insight-driven strategy firms such as Innosight are in the [business + culture] overlap, and human-factors firms such as Cheskin and Point Forward are in the [culture + design] overlap.
I also found that Jess McMullin had categorized design consulting firms in 2005 (a blog by Jess McMullin). He compared ‘design’ consulting firms with ‘traditional’ strategy consulting firms such as McKinsey.
Does anyone have any updated list? I hope to update this post and to make it as a comprehensive list of design consulting firms.