The OP had it right in that some of these bitsa basses are like custom shop creations. I picked up this one a few days ago and have worked on it a little. Done a nice setup with lighter Elixirs, and added some better foam on the bridge pickup, as it was sinking too far away from the strings. Just been out and done some new outdoor pictures, too.
The constituent parts are; Fender MIM roasted maple neck, Schaller tuners, 'Guitar & Bass Build' high polish Alder body, Hipshot bridge (only bridge I've ever seen that needs a 0.05" Alun Key!) and active EMGs with a 9v battery under the gold tort scratch plate. A very lively and snarly sounding bass - think of it as a non-pink Betsy.