Athearn just announced on Dec 28, 2018 that it's coming out with 40' standard-height containers, expected next year (December 2019)!
Sea names for the first releases of Athearn N scale containers include Xines, OOCL, Matson, Maersk, CMA-CGM (old logo) and China Shipping.

This makes Athearn the 12th major manufacturer of plastic 1:160 scale intermodal containers after Atlas, Con-Cor, Deluxe Innovations, Fox Valley Models, Hobby Train, Jacksonville Terminal Co, Kato, Micro Trains, Rolland Industrial Ltd, and Walthers.

No word yet on whether the new Athearn containers will be stackable with other container brands.