I wrote this up on the Woodwind Forum a little bit ago:
Again, while researching something completely different, I stumbled upon http://www.music-company.be and an interesting — and unfortunately very small — picture:
It’s supposed to be all of 20cm in length.
Paul Cohen wrote two articles on the Bb curved sopranissimo in The Saxophone Journal (“Vintage Saxophones Revisited”, May/June 1996 and November/December 1996). The curved Bb sopranissimo was hand-made in 1960 by Robert Vanlinthout in Brussels.
Comparing the pic in the Cohen articles and the picture above, there are some differences. Additionally, the length of the horn quoted is 19.5cm. The one, above, is 20cm. However, the store IS in Brussels. Maybe Mr. V made another prototype.
I think I’ll try to write them and see if they have more pics.