I wouldn't know about them being as common as the Hi-Saturn. But which model are you thinking of? I've come across plenty of Model 2 consoles, but model 1 V-Saturns are pretty hard to come by.
They are not really rare. I have a model 1 Saturn and it was neither too hard to find nor more expensive than any regular jpn Saturn in the same condition. I can't provide any numbers though.
