For years, I played double neck guitars and bass pedals. On one long standing gig, I played the bass neck along with a "sing-along-" entertainer type...Preston Weber, probably the highest paid entertainer who worked in Lexington. When it came time for a solo, I switched to pedals and played the guitar neck.
For 5 years, I played an Auto Orchestra, where you held the proper bass note and triggered 7ths, minors, etc. with the heel and toe of your right, volume pedal foot.
I did a single with a double neck 6 and 12. I had the 12 string neck into a 147RV. I had a drum machine and a set of pedals.
When my long-time organ player was having lots of physical issues, I played a Rhodes finger bass over an early Honer Clavinova.
Ah, the things you do to get girls!
Russ