Back around 2015 Peavey shut down their manufacturing operations in MS. When they did, apparently they pretty much turned off the lights, locked the doors & walked away. Last year, one of the moderators of a FB Peavey group I'm in was hired to liquidate all the oddball leftovers scattered across multiple buildings. I messaged him & asked him to let me know if he found any oddball lefty bass stuff & a few weeks later he sent me pics of this.
It's a 1-off prototype bowling ball-like finish on an otherwise stock body(though somewhat rare in the fact it's a lefty alone). I picked up for $150, but wasn't immediately sure what to do with it.
This would have originally been a standard(34") scale length, but due to reasons I only play 30" basses. However, there's no off-the-shelf solution - simply bolting on a 30" neck would typically require the bridge to be moved forward, occupying the same space as the rear pickup. No one really offers a custom solution without going 100% from $cratch custom either.
So the project sat around for a few months until I stumbled upon this set of NOS pickups that I got for $80 off Marketplace a few weeks ago.
That inspired me to get started, so I figured I might as well tackle the neck, since everything is dependent on it & the bridge. I picked up a 30"-scale Eden "paddle" neck of eBay for $69-shipped. One cool thing is it has marker dots on both sides of the neck, so it works for lefty's too!
As you might guess, it's called a "paddle" neck due to the uncut/shaped headstock. For those not aware, an 8-string bass is similar to a 12-string guitar. There are 4 pairs of strings tuned in octaves. This will require 4-bass tuners, and 4-guitar tuners laid out 2-each per side. So the final headstock shape will be determined after the tuner location is set.
If I'd left the neck as-is, it would have required the bridge to be centered slightly past the 30" mark. Hence the first obstacle.
Both the neck pocket on the body and the heel of the neck are tapered to provide a snug fit, although the neck is larger than the pocket. This actually worked out to my favor. Here's where I decided to make my cuts.
Some of you are probably wondering "what about the truss rod?" I decided to just watch for metal shavings while feeling for any change in density/resistance as I was sawing.
That didn't work out too well...
Oops. I think I'll be ok though. There's a very narrow gap between the trimmed neck & the body, so I'll just make a shim that I can glue to the underside of the neck that'll cover up the exposed truss rod & keep it wedged in place against the body.
On the plus side, trimming the neck resulted in a perfectly snug fit!
The heel joint looks off due to the trimmed neck, but fortunately there's still plenty of meat where the screws will fasten it.
Next on the list: I need to order about $40 in hardware - a neck plate & screws, the tuners, strap locks, knobs, and pickup mounting screws. Then I need to order this bridge for $250. Ouch. I'll also need to order strings, which will probably be $35 to piece together a set. There are a couple brands that offer a packaged 8-string set, but I don't like the gauges they use.
Once I get the headstock cut to shape & painted black I'll contact my local luthier & schedule a time to have him cut a nut for it. The one on the neck is already cut for a 4-string, which doesn't leave enough room for the high octave G-string, and I want a graphite but anyway. I'm hoping he'll have a leftover piece of plastic I can buy to cut into a cover for the control cavity on back too.
I have a j-bass that is missing something I think active pickups would provide 
