Greg, thanks for sharing what you've learned. I'm not sure I'd stay away from the neck side scarf joint though. If a headstock laminate can provide enough strength to a headstock side scarf joint, then a fretboard, which is stiffer because it's thicker, can supply as much if not more strength to a neck side scarf.
You could end up with the same problem on a headstock side scarf joint as well and then, you'd experience the same problem under the headstock laminate as you did under the fretboard.
To be honest, I'm afraid of trying a scarf joint although, my next project (explorer, bolt on) will probably have one.
Great project!
Dave