Chet, I've recently finished a tenor-to-5-string conversion by building a neck, including slotting and fretting a fretboard from scratch. If that's the part that has you worried, I can assure you that if I can do it, you probably can too. If you're worried more about the pot (like where to get a 9 inch one), check out "Making Musical Instruments" by Irving Sloane, "Earl Scruggs and the 5-string Banjo", and "Foxfire 3" for some ideas of how to go about building one.

Jon W.