Some companies (like MediaVentures) or groups of people can be in a position to create a "custom" library, which they cannot or do not want to sell commercially. There can be several reasons for that (non-disclosure agreement with the orchestra, or simply no interest in the marketing and sales work required). If you read interviews with welknown composers, there are quite a few of them who have such "custom" libraries.
It may be something to be jealous about, but as Craig says, nothing beats VSL, so don't get overexcited.
It's just that this darn Norwegian guy can do magic with ANY library [;)]
Peace and fun,
Peter
www.PeterRoos.com