You can now download the Terminal map as free DLC. Its only available on the Xbox 360 currently but am unsure if it will be released later on the other platforms, like all other DLC. It was available to Elite subscribers on the 18th July and non-Elite subscribers on the 19th July, today.
Loading screens were found in the game files of MW3 just before it was officially announced:
A few small changes were made to the map, mostly aesthetics wise.
Find the list here: