Ah, good that you created this topic, otherwise I would have started one today. 
I was looking at fader controllers like the Sparrow 8x100mm MIDI controller ā The MIDI Maker, and wondering what would it take to use it as an Electra 1 extension.
Iām thinking especially on the DrivenByMoss for Bitwig and Reaper extension, where the mixer is already organized in blocks of 8 channels.
I wonder whether an 8 faders controller could be used here. Bonus points if there is a way to use a 4 faders or smaller numbers and have a way to jump to the next/previous bank. I was even thinking about the possibility to plug a top quality 1-fader controller and use it in combination with whatever is active on the E1.
For what I have seen, these dedicated fader controllers tend to have some way to configure their MIDI signals in detail.