How about zinc phosphate primer plus cathodic electrocoat?  Or maybe a multilayer organic -e.g. Dacromet, although there are superior products.

What is the operating temperature expected to be?  Any potential for wear?  CoryPad gave some good candidates if ambient temperature is the predominant environment.  I would recommend coatings from Magni instead of Dacromet, but that's mostly personal preference.  

Cadmium coatings (vapor deposition instead of electroplating) are used for a variety of aerospace applications.  If you can provide some additional details, we can help narrow down the candidates.

The temperature is 15F to 120F.  The coating should be tough enough to be handled and moved by cradles and carts.  

Depending on the duration of salt spray resistance, it sounds like any of the above would be suitable.  Some rough estimates for corrosion protection in a salt spray/fog environment (ASTM test method B 117) are as follows:

1. zinc phosphate + epoxy electrocoat (25 micron thickness) = 500 to 1000 hours.  Higher film build will give up to 2000 hours.

2. Magni or Dacromet = 500 to 1000 hours, depending on film build and exact formulation.

3. Cadmium (I meant vacuum deposition not vapor) = 96 hours at a typical thickness of 12 microns.