I know you are talking about moving from Argentina to the U.S., but when we moved from the U.S. to Argentina, we used a U.S. based international moving company (Wheaton) who organized the container and shipping with Mediterranean Shipping Company (MSC) and then sub-contracted local movers in the U.S. and here in B.A. We filled a full 40 foot container which meant there was no chance of anything getting lost (except the whole container I suppose). We were pleasantly surprised with the excellent quality of service of the Argentine company (KRP Moving), in fact, after the container arrived at our house and they unloaded, unpacked, set-up beds, desks, etc., hauled away the trash, Lucas Kent (son of the owner, I think) came out to our house to follow up and make sure everything was OK and we were satisfied with the job. I would certainly use them again. Another big international moving company here in Argentina is Transpack, although I have no personal experience with them.
One thing to keep in mind and check out (perhaps call Lucas Kent, he speaks English as I recall, not sure if that is important or not), when we moved from the U.S. to B.A. in 2006, the U.S. (or perhaps some International law) prohibited us from doing any packing; the moving company had to pack everything. This is so the moving company can certify there is no hazardous material in the cargo. The only thing that we could do was pack a few things in those clear plastic boxes. It actually worked out very well for us, although a bit stressful to see your entire life’s worth of “stuff” driving away in a container.
So, I am not sure if you can “crate your stuff and show up at the dock looking for container space”.