surprised it has been taken out of X3 - it was a Kjaerhus effect, right? The sale to Gibson shouldn't affect that. Kjaerhus had some issues and maybe stopped producing software, as I remember, so perhaps the licensing couldn't be perpetuated?
Any ideas about why it was lost?
I never really got into the VC-64 anyway, something about its interface made it seem unwieldy to me, but I think I did use it a few times in some old music, which means I have another reason along with V-Vocal to have to keep previous Sonar version installations around.