Judging from the links in the Wikipedia page and the other reply to my post, i think it was Looking Glass what i remembered, but this was also very interesting

Judging from the links in the Wikipedia page and the other reply to my post, i think it was Looking Glass what i remembered, but this was also very interesting (especially the part about modifying Motif to look like Windows 3.1) :-). Sometimes i wonder how hard it'd be to modify OpenMotif to add theme support.