So I saw this on a Facebook page for Jazzmasters, not sure if the guy's a member here, if you are, kudos, and please give me your blessing to do this myself. (Also sorry it's not *quite* a twelve string.
Here's the guys post, with a vid link:
I've just finished (well partly) a prototype of an idea I've had for about 15 years. The idea is to have a 12 string, where 6 strings are fixed in a tele style bridge, and the 6 others pass the bridge to a Jazzmaster tremolo. I was hoping for a manually controllable chorus sound.
For this iteration, I got a cheap but decent Harley Benton Jazzmaster copy, and installed the tremolo and a half ashtray bridge. I had to raise the bridge with a piece of aluminium to get the right angle for the strings. I could easily fit 3 extra tuners, so at the moment I settled for that.
The result is less exciting than I hoped for, but I'm starting to figure out what to play to make it sound the way I dreamed of. Maybe I will experiment with having the D, G, and B strings doubled instead. I will also install a pickup behind the bridge for more atonal sounds.
If anyone else has tried this, please share your experiences!
Sorry for the hum in the video, I haven't connected the ground wire to the bridge yet. Also for the guitar playing, haven't touched a guitar for a couple of years
https://www.youtube.com/watch?v=J-inbM3yJZQ