RVHP already does the 1900C in 1/72 and I hear that a 1900D is due in 2012. If true, it will be the best on the market. Liberty Model did a resin 1900D with Delta NC markings (and AF). A bit rough, but could be built into a decent representation.
Broplan's SAAB is vacformed in some of the thinnest plastic I have ever seen and the kit needs quite a bit of TLC. The decals the kits come with are next to useless. For the price, it is unfortunate. The shapes are there, though.
RVHP has SAAB 340's listed as coming soon (along with GIV's) in 1/72. Again, I'd try to obtain one of them when released.
Welsh's 1/144 SAAB is decent, but it has some shape issues up front (that SAAB 340 "face" is hard to get just right).
Mike