http://www.glassmessages.com/index.php/topic,38037.new.html#newShugdens has found a lamp base with mica and combed effects with a "Made in Czechoslovakia" label, (above link).
The base is very, very similar to a strange thing in the non-Ysart glass - under the heading of Bohemian/American United Glass?
(I've put the link to Frank's site, relevant page, in the thread)
I just thought I should bring this labelled piece to Scotland's Glass' attention.