IC Green designs and builds "modern and sustainable pre-fab dwellings made from converted oversea shipping containers".

They currently offer 6 models:

Model	Size	BR	Bath
320	320 sf	0	1
480	480 sf	0	1
800	800 sf	1	1
1280	1,280 sf	2	2
1600	1,600 sf	3	2
2400	2,400 sf	3-4	2

Check out their construction photos.