Here's a labelled SVd'A piece. As I wrote, I think many companies produced these ribbed vases. I think the piece is of a slightly better quality than the one you show, Ross, although your piece is definitely better than any of the "Genuine Venetian Glass" pieces I have. PIna's "Archimede Seguso" shows on p. 41 a diagonally ribbed (created by twisting the piece in the optic mould, I think), which has similar colours.
However, I still wouldn't say this is definitely an Archimede Seguso or SVdA piece; just that it looks like one of the better made pieces.
David