Check out http://letstalkguild.com/phpBB2/viewtopic.php?f=6&t=15198 for video of a neck replacement on a Guild Starfire. The way the luthier in that video preserved the headstock face (w/the perloid inlaid logo) was interesting and would do a lot to keep the original feel of the instrument. The integration of an ebony laminate in the replacement neck would increase the fundamental frequencies and sustain in the bass's sound. Replacing the neck might suggest refinishing the body(?). Good luck. Keep us posted.