Concerning Yamaha VP1:
Not true, there's probably 10 to 20 pieces, most of them are in Japan. I'm maybe the only musician who has recorded double CD "VP1 Impressions" in 1997 at Yamaha Europe in Hamburg, Germany, on one of three pieces which were in Europe. I could buy it for good price but still too expensive for me. So that one was bought by Austrian colleague, later he sold it to one German doctor who still has it in his collection. There are threads about it in some other discussion forums. You can hear some of my improvisations on my page
www.soundclick.com/forrotronics
And thanks to my cooperation with Yamaha as a Product Specialist, Demonstrator and Clinician I'm one of the first musicians who started to use VL1. Still I have two pieces, plus two VL1m, and more VL engines in other instruments. That's a pity Yamaha abandoned this way...