1. This would require the VST to be capable of outputting MIDI. And, I'm not sure, would this be for things like updating the LEDs on the sliders and such? If so, the QuNeo already has specific MIDI CCs that will update the LEDs when received. There are diagrams on pages 38-39 in the QuNeo Full Manual that show all of the messages and what they control.
Though perhaps that's the point of your request, the ability to change what message they respond to? If so, that's been logged as a feature request already.
2. There is the "Enhanced Note Mode" project: http://www.keithmcmillen.com/project-de ... -note-mode
It covers the various modes, Ionian through Locrian, and also has Major and Minor Pentatonic. Root note is selectable. It only operates in drum mode though, not grid mode. The package includes a Max/MSP patch, a Max 4 Live device, and a standalone application.
3. Yeah, I always found it odd that we didn't put dedicated bank switches on the QuNeo. But I think the real problem with adding even more banks per preset and having completely different settings for banks (or at least just different notes) is simply available memory/space on the QuNeo. I'm pretty sure it's pushing toward the limit already — adding more could potentially put it over the top.
4. Hmm, well, while the long slider can indeed detect two fingers, it currently cannot output the location of the two fingers as separate MIDI notes. Right now the multi-touch on the long slider only sends a CC "width" parameter — the distance between the two fingers.