Any chance you have any open source links that discuss how you practically operate a system based on the concept you describe (manual query rewrite w/i a session as your data set)? Perhaps it's obvious to an NLP person how to reduce that "idea" to practice, but it is not to me!
You're definitely right about the idea though - a former Search engineer obliquely mentioned that this sort of session based manual query rewriting was very core to how the synonym system worked.