Rokugan is low magic, in the heart of the Empire. Along a certain border there is as much magic as the Empire and the Crab Clan can muster. A great setting if you want an oriental flavor. But it is largely Japanese with some chinese and other neighboring cultures thrown in. Mostly as legends and monsters. The "culture" of Rokugan is strongly based on Japanese.
Personally I enjoyed the setting most with the L5R d10 rules set. It really adds to the flavor of the setting.
Of all the settings mentioned, and I have played or own and read many of the books of every setting mentioned, except Eberron. To me it is a setting on some kind of drugs. Definitely not a setting I would choose, and I have chosen not to get it. Anyways, Kalamar most closely fits all your criteria with a minimal of fuss.
Ptolus is a good setting, if you want a city. Plus if you don't mind the $120.00 (US) price tag to get in the door.
If you do get Kalamar you may or may not want to bother with the Players book. If you look around you can probably find it pretty cheap, and there is worthwhile material in there. But it is not critical to using Kalamar as a setting, but it would definitely help add some dimensions to it.
The world Atlas is awesome!! I wish every setting had an atlas like this one.
The Scarred Lands could be run low magic, but personally I think that would be a disservice to the setting. Everything going on with the Titans, The City of Mithril, the Necromancers, the various races, magic would have to be prominant to do SL justice, IMO. (I know, Nighfall, I know. You are "the" Sage of SL and all, but the big cool elements of SL demand a fairly high level of magic in my view.)
The only other setting that would fit is Wilderlands, but it does not have specific module support like you are looking for. I have found it extremely easy to fit many modules into the setting though. So in my view looking for modules specific to a setting is cheating yourself. I'm a module whore, though, so do it however you'll feel comfortable.
For the record, my current favorite setting is Erde, by Troll Lord Games. It also has everything you want, mostly 3.0 versions though. The setting book is badly laid out and can get confusing fast because of it. All I can say is the "flavor" of it grabbed me. Guess I am a sucker for "german" flavored dwarves, english humans, and "french" flavored elves and turning real world European (and others) legends into Erde myths. It just works for me.
Hope whatever you try first works for you.