I dont know... my kids realy love Alien Conquest, which has a rather retro feel to it too... Though, they go more for the ADU stuff, while I already knew I would get the alien saucers, the real "retro" aspect in the line, the first moment I did seem some leaked pictures.
So why not something inspired by above mentioned examples? Its true, for most kids those series or movies wont mean a thing, but, it doesnt need to be something licensed. Preferably not. Just inspired by.. the general feel.
In fact, what I would like to see is a Lego product line based on the Trigan Empire comics of the 70's - 80's?
It has all for a wide range of Lego fans: spaceships, different (alien) races, monsters and dragons, futuristic and classical buildings, references to ancient Roman and Greek.. I guess there is there something for everybody, except city fans..
Or, if some Lego executive decided there is need for an AFOLs only line: what about Barbarella??