Ok, let's clarify the things...
Only the people behind the GPL (the dev & such) could ask a lawyer to resolve this copyright problem, maybe the people who have added something in the source lampshade is using (Ighalli for exemple in the CVS version, and only for the part he was involved in I think). Nobody else. You could tell the dev about this problem, but they are the one who choose.
So, without any dev asking lampshade to release his modified source, it's useless arguing...
And last... Sorry for my english