EnterpriseDB, Command Prompt, 2nd Quadrant, and all the others listed under http://www.postgresql.org/support/professional_support/

Many of those companies have people on staff who are members of the PostgreSQL core committee, or at least have commit bits. Can MySQL say the same?

If your response is going to be "But that's not commercial support from 'PostgreSQL' itself", that's the nature of the community. It was a deliberate choice by the community to structure itself that way: PostgreSQL — the community, the brand, or whatever you want to call it — can't be sold. This is a good thing, and I don't think I need to waste much time explaining why...