I'm not saying you add more midi guitar notes to make up a C69 on the guitar track. I'm saying for a C69 let the guitar play a C strum, let the string or pad play a D5 and the bass play C. Want a Cmaj#11? ok, let the guitar again play a C, toss in a Bminor on the piano, then you've got your Cmaj#11. Offcourse this is just a theory on how you could do this in the simplest form, you could offcourse use more chords than just the four basic chords. Virtual Guitarist is a little bit of a different beast. The first version used a bunch of loops, the new one uses a blend of loops, samples and midi. But this thing is a Guitar simulator (Much like RealGuitar) And you have quite a lot more chord choices in the newest version of them both. If you want to check out how stretching algorithms can really improve pitch shifting, check out Melodyne and SampleTank 2. I use Melodyne all the time for fixing pitch problems in voice recordings, but I also use it a lot to generate vocal harmonies, transposing recorded instrument parts it's great! SampleTank has a stretching algorithm that transposes samples really good! Both of these algorithm in both applications transpose the audio without changing the lenght of the sample, just the pitch is adjusted. Normal pitchshifting involves running the sample faster or slower to get the desired pitch result, hence the chipmunk effect. This way however does not give you the chipmunk effect, you have to try it out for yourself.

Check out http://www.nativeinstruments.com for Sampletank
and http://www.celemony.com for Melodyne.

If you could incorporate this type of approach into an arranger, you will get more realism than you ever thought was possible. But again this is just my theory on how Ketron could achieve the result they are claiming to produce, I have no affiliation, nor any information regarding what their solution is all about.

Doc-Z