Migration from PDF, MS Word and Frontpage?

l337hx0r asks: "I've just began work at a government department who, with 24 branches and five years at their disposal, has managed to create 85,000 proprietary documents. The current IT manager doesn't see a problem with this, and the government recommendations of open formats came as quite a surprise. I want to move this intranet away from WYSIWYG to a logical document structure (Docbook, Tex, XHTML), though the migration tools have been quite disappointing. Can it be done?"