Looking great Rob, can't wait to see where you go with this one as the piezo idea is something I've been thinking about for a future build too (using a TLB-4 kit so not too dissimilar).
Have been thinking about a 5 string P or J Bass as a project since I started looking here recently..... But wasn't sure if there was a possibility to get a 4+1 neck made... You have answered all my questions (prayers) and got me very excited indeed.
The headstock shape you have here is also a bit like that used on the Tune basses... I'm a bit of fan of the traditional F style personally.....
Whats the plans for body finish??
Definitely going to be following this build....
It's not going to be easy to make a truss-rod cover as the headstock's quite curved at that point (unless it was a very thick one that had enough depth to incorporate a curve). You don't want to flatten the curve of the headstock as this would thin the neck at a structurally weak point. So I'd have thought that you just run the veneer up to the nut and cover up the gap that way. You wouldn't want to stop the veneer short of the nut as you'd have an obvious line.
There should be some scrap left over from the bit of rose wood that was removed that you could use it in front of the 'Adjust-A-Nut' to cover the exposed truss rod channel.
# 1 - EX-5 http://www.buildyourownguitar.com.au...t=4257&page=10
# 2 - EX-1 http://www.buildyourownguitar.com.au...t=4551&page=10
# 3 - Non PBG Tele - unfinished http://www.buildyourownguitar.com.au...?t=4812&page=3
# 4 - Non PBG J Bass http://www.buildyourownguitar.com.au...?t=4813&page=8
# 5 - TL-1AR - under construction http://www.buildyourownguitar.com.au...ead.php?t=6792
Loads of options!