I sent some messages around to the usual suspects about making some container markings. The answers I got were "too busy", "don't have the equipment to do anything this small", "worried about copyright protection", or they just didn't reply. It would be nice if somebody with the right equipment would step up and do something for this kit but I'm not that guy and I don't know who will.
I think a reasonable job could be done by going with a load made mostly of Hapag-Lloyd containers, using the kit decals for those, and then some different colored containers mixed in with lettering that can be done with either a artist pencil or well placed dots of paint to represent letters. Let's face it, in 1/700 scale they're going to be pretty tiny anyway.
I also think that carving down and carving up some of these containers is a good idea. I need to explore this further but I would think that some of the side panels cut from the bottom of a stack could be used to fill in areas carved out above, if that makes sense. And what the heck, why not scratch build some flat racks to boot! Maybe a tank container or more thrown in as well.