Well, I was a little unsure just seeing the line drawing in the pattern book, but if you look closely at the link above to Vizner's models (1973), there is your fabulous vase, in colourless glass

PN 7350/18
So not a prototype, but a rare production piece.
(added: Irregularities are totally common in Skrdlovice glass from that period, so I wouldn't worry too much about the shape not being perfectly cylindrical)
The 4th pic in your blog looks a better match, shape wise.
BTW - I totally love your Murano glass collection (and photo skills).
Michael