You might look at the Selle San Marco Atola. It would seem to meet all your requirements except it might be a tad heavier than some of the very lightest-weight saddles. It's really comfy, though. The only problem it ever gave me is a little sit-bone soreness when I first started riding it (or if I go for awhile without riding). If you're already used to harder saddles, like the Zero, that should not be a problem for you. You might also look at the Terry Falcon Y (the men's version) if you need a narrower saddle than the Falcon X. The Atola is narrower (140 mm).
I got mind from Colorado Cyclist, but I couldn't find it on their site when I checked just now (very quickly).
Good luck!
Emily