20ft Shipping Container K Line (Subdivision ready 3D model) is available on CGTrader for $29. Original author: dragosburian. Specs: 93270 polys, 96414 verts.
STL (Stereolithography, filesize: 4.34 MB), OBJ (OBJ, filesize: 7.81 MB), FBX (Autodesk FBX, filesize: 5.01 MB), DAE (Collada, filesize: 4.82 MB), BLEND (Blender, filesize: 14.4 MB)