re: blackness --
I think you'd probably find capping from the Japanese 'Collector's Set' quite interesting: it's the same NTSC transfer as 'Faces' and the DC, but it's noticably darker right off the top. I suspect it has something to do with the fact Japanese NTSC is IRE 0, while US/Canada NTSC is IRE 7.5. Or something like that. I think I've got it right, but I'm no member of the ITU or IEEE...
re: my caps --
Here are three caps. I've tried to get the exact same frames as you; these were the easiest. The two space ones are without any enhancement at all -- just resizing. The face one has some sharpening (thanks, Laserschwert!) applied, but otherwise that's it. Well, except for resizing again, of course.
I think I will probably eventually get around to some colour correction. At least on the corridor shots, I think everything's a bit yellow-looking. For the meantime, suffice it to say that these caps are not optimized. Like you, I'm interested in getting the best. With all the tools available, everything starts to blur and it gets really, really tough to know what looks right anymore. Also like you, I'm keen to hear from some interested observers as to how I might tweak things to make the results better.
By the time I'm done this monster of a project, I suspect I may have broken the thing down shot by shot and tweaked everything a bit!
(P.S. You'll notice the bit of crud on the very right of the first cap, on the brown surface of Tatooine, just inside the bluish halo. That's the sort of stuff I've been rotoscoping out. I've probably done this frame already, but I re-capped this LD side recently and haven't gotten around to re-aligning the script to replace the frames I've fixed.)