Let's not consider mods.
IMO, and in no particular order:
Roland G77. The "sustain bar" (black hanger) is even more peculiar than the MIDI capability:
Ibanez Ashula. I am certain Jaco would fiddle with this:
Ibanez SRKP4. Integrated Kaoss Pad:
Any bass with a tremolo. Here is the Washburn Bantam Whammy:
What else?
IMO, and in no particular order:
Roland G77. The "sustain bar" (black hanger) is even more peculiar than the MIDI capability:
Ibanez Ashula. I am certain Jaco would fiddle with this:
Ibanez SRKP4. Integrated Kaoss Pad:
Any bass with a tremolo. Here is the Washburn Bantam Whammy:
What else?