Sometimes it better not to reinvent the wheel.
I kind of took a lesson from Greg Roberts and improve a known speaker design. Greg took the Klipsch design and re-worked it into the masterpieces he has. I kinda followed the same lead using an old Cerwin Vega H15 as a base. New drivers, crossover, modifying the bracing, baffeling etc. The latest version sounds pretty darn good for a tinker like myself. CV like Klipsch, put a lot of effort into getting the cabinet design about right. It was just of matter of refining it and using new state of the art drivers and crossovers.
You might call it cheating, but it seems like the best way to go if you are after good sound from an old box design.