I thought it about time to resurrect this topic again. From Jason's comments elsewhere, the rulebook should be about to go into production. The need for a generic set of SF rules will imminently become VERY REAL.
Contrary to my earliest reaction to the idea, GURPS Space makes a fine model for the kind of content which is needed. I feel that, whether or not actual systems for designing gear are published, there should *be* a system so that the goodies which would be in the supplement (weapons, spacesuits, starship components, sonic toothbrushes) are consistent and can be easily expanded upon.
I know just the person to ask about world generation. That still leaves ship/vehicle building and general gearheading.