Yes, strangely, even tho I am a Noah owner and have SixString, I never actually tried this Piz plugin with Six String! Guess I always just used a guitar!
I've used other plugins from his suite - for example, the Midi LFO is a standard in projects now sending CC to my Vermona Lancet for PWM, to add an edge to an aggressive bassline... It's such a comprehensive set of plugins that it's worth familiarising yourself with the range.
I also have a YouRock Guitar (with Midi Out), bit of a toy, definitely not a guitar, but I still find it far easier to improvise on a fretboard than on a keyboard, either guitar or bass lines. I say it's not a guitar, because you cannot pull off to a open string or do string damping, or accurately control hammer-ons or pull-offs, or bend strings for vibrato (stuck with the unfeasibly long yet ultimately trimmable whammy bar for pitch bend). And yeah, I have to clean up the Midi afterwards - false triggers, velocity variance - altho the mipressor (midi compressor) plugin does help (another useful freebie:
http://adam.fulara.com/software). The fact that the YouRock has an internal little synth and a headphone out jack means you can noodle away learning the vagries of its use while the wife is watching TV!
They've recently released YouRock Guitar mk2 (something like that) - apparently, they made a point of addressing some of the well-reported problems, such as those I listed above. Just wish there was something in between the low-priced YouRock and the far more expensive Starr Labs guitars... altho there's little doubt but the Starr Labs are superb instruments, and you do get what you pay for by all accounts - i.e. a playable gig-worthy instrument.
What you're saying about integrating something like this - an open-source project handling pure Midi - into Open Scope is very interesting. It really would --open-- things up!
Not because it is easy, but because it is hard...