First of all, I assume by sustainer guitars you mean guitars with electronics that allow infinite sustain, right? *Although I checked out MusicYo.com and couldn't find what you're talking about.
I think it would be much easier to put a
Fernandes Sustainer system into one of your existing guitars or into a new guitar. *I don't know much about the Kramer system, but Vai himself uses the Fernandes system. *It has feedback/harmonic modes that allow control of harmonics, etc. *It's a simple system really, just the sustainer pickup, the sustainer level knob, a couple mini-switches (sustainer on/off, harmonic mode), a battery case, and a "high-output humbucker" which you can, I'm almost 100% sure, replace with a pickup of your choice. *
Or, even easier, is to buy one of the Fernandes guitars with the sustainer system built in. *They have all sorts of models, with either their "high-output humbucker", Duncan JB, or EMG HZ pickup in the bridge. *There's even a 7-string model now.
Here's some info on the sustainer system:
http://www.fernandesguitars.com/Misc...index_Sus.html
And here's a link to where you can order a free catalogue. *I've got the catalogue, and it's got some amazing models.
http://www.fernandesguitars.com/Misc...index_HFC.html
The site hasn't been updated in a while, so I'd recommend the catalogue.