Michael Cretu (Enigma) - that would be amazing, considering that Cretu also has not published any new record for about 7 years now, and E8 is supposed to be done in several months.
Klaus Schulze - I don't think Klaus would decline. And this would be the most exiting and crazy thing to do!
Vangelis - little chance here imo, but who knows
Kraftwerk - even less chance
Schiller - the leader of modern German EM scene
Michael Rother - his melodies are priceless
Kitaro - will definitely agree, but not sure what the result would be
the PRODIGY - I am serious here, the most creative EM band at this time, a must
Sebastien Tellier I think will be there anyway
Deep Forest (another French artist of very few who reached high international success and belongs to electronic music)