So as part of my build with Andy I've been doing loads of research into headless basses. I've managed to find loads of parts and possible alternatives to the "traditional" stubby end to a headless bass.
I found this site which stocks loads of parts to build a headless bass.
http://headless171.rssing.com/chan-56698534/all_p1.html
Unfortunately I've already bought most of the parts we'll need but there's no point in reinventing the wheel.