Thanks, Astrid. Pity that the Museum people didn't answer so far -- they seem to have the old catalogues, which migh help a lot in attributing unknown pieces, or in finding out designer and production date.
Your vase seems to be the most common (confirmed) Ichendorf design around; I have only seen one of them in real life, and they are very nice -- and very nicely executed.
Vases like my bubbly piece seem less common; I bid on one last November but didn't win it, then there is mine (which was on ebay for almost a year till I finally decided to contact the seller), and the one from the artglassleiden site...
But I have only been looking for that kind of vase for about a year, so not so scarce maybe.
edit: the Duesseldorf e-museum site refers to Ichendorf catalogues from 1973-75, unfortunately not available online, but they give a few designer names:
1973: Ichendorf-Design, Heinrich Sattler, Ralph Michel, Alfred Günther, Gilbert Kruft, Ulrike Penkert, Marianne Penkert, Gistl-Design
1974: Ichendorf-Design, Heinrich Sattler, Werner Bünck, Ralph Michel, Alfred Günther, Ulrike Penkert, Marianne Penkert, Gistl-Design
1975: Ichendorf-Design, Heinrich Sattler, Werner Bünck, Alfred Günther, Ulrike Penkert, Marianne Penkert, Wolfgang Klapp, Gistl-Design