The City had so many pots on the fire, they stopped doing sub-plans. They turned instead to a 2-step process of developing a single master plan. Amendments to the old plans were completed and released in April 2012. Updates re Fairfax Boulevard are included in that document as Appendix D. Phase-2 drafts for new master plan elements are not complete at this point.
http://www.fairfaxva.gov/government/community-development-planning/major-projects-plans/comprehensive-plan