The following four kits (all of which I have in my stash), are all described by Rajens' as "Cold (War)…Freighter" - and they are all modern (i.e., post-WWII) ships, but all very distinctly different vessels, per the following:
This is a classic cargo ship - the direct modern counterpart to the earlier, Revell Hawaiin Pilot, for example - except again, with a beautiful, full hull. Note it is right at 400 scale; within your range of interest, Jim.
This is another modern cargoliner - but very different than Bahrain, above; having fewer derricks, and again a different - but again very plausible-looking - full hull. And this one is directly in the center of the 1/400-1/500 scale range of interest.
Roll-On/Roll-Off Ship 1:450
Like the others, described by Rajens' List simply as a "Freighter", this is in fact a "RO/RO" - a "Roll-On/Roll-Off" container ship; in which complete truck trailers (and vehicles for delivery) are driven on and shipped en masse, to be simply driven off again at the destination(s) - the mold comes complete with a moveable, extending stern ramp. It is a truly classic kit (though I haven't yet built mine) - and again, note it is dead center in your target scale range; at 1/450. Rajens' also notes that, "With a bit of haze grey paint, you could easily make this kit into the Cape Kennedy (T-AKR-5082) or the Cape Knox (T-AKR-5083)"; again, a modern counterpart of a merchant design working double-duty for the Navy as well.
This is another vessel for whom Rajens' description as "Freighter" does not do justice to the reality of its design - and size - as a huge container ship. Ergo, note its smaller scale; while coming in the same sized box (approx. 20-inches long) as the others, above - but again, it is a distinctly different mold, from the keel on up through the entire superstructure. I can't recall if it actually comes with a pile of (deck-stowed) containers, as depicted by the box art. Especially with these depicted, it could make a very impressive build.
So, that's the IMEX line - not a lot of subjects, but for a merchantman enthusiast, some real classics - and good quality - to be found here. Even better, I've seen all of these lately available quite inexpensively - like, for $15.00-$20.00 - which of course is why Cheap Uncle Matty has snagged (at least) one example of each.