Built: Summer 2010
Materials: PVC pipe, 23/32" pine plywood, threaded rod, guitar hardware, piezo elements (pickups)
The plans are designed so that you have a choice: build a one-string bass or build a one-string electric lead. My thought was: why choose? I'll build a double-neck!
I also modified the body from those in the plans. The plans have you bolt the PVC neck onto a plywood body cutout. I wanted the neck more flush with the body like in a real guitar. In the picture below, the body is actually three pieces: left side, center (between the pipes), and right side. Each piece is actually made from face-glued strips of 23/32" plywood -- in other words, what's facing you is the plywood's edge grain. I did it this way so I could use threaded rod to through-bolt the body pieces and the PVC necks (if you look closely you can see the end-nuts at the edges of the left and right body pieces).
Each neck has it's own piezo element pickup. I didn't install any kind of internal "mixer" so I need a separate patch cord (standard 1/4" guitar cords) to my amp for each neck. The cords plug in on the bottom end of each neck.
Technically this is not finished yet -- I still haven't gotten around to putting the zip-tie frets on the bass side.