For me its tough to vote. I would rule out comet simply because its such a cheap game, most people wouldn't want to stick the extra money into it. I like the idea of Pharaoh but its a pretty low production run. I think you should do a game like black knight personally. I know they made repro PF's for it, but now they are hard to come by. Not to mention not everyone has the kind of money to sink into a repro PF (such as myself). Plus there is A TON of BK's out there that have badly worn PF's and it is a desirable game.
I think space shuttle was a good first choice, because of most of the reasons I listed above about BK. Your other options just don't have the same kind of draw. Some other good candidates IMO would be: Centaur, Sorcerer, eight ball or EBD, Xenon, Pinbot ect.