I'd maybe start with a polyCylinder and polyCube, set them into correct positions (distance between faces is 7 units) and then set the number of sides equal and bridge them together. Before bridging I'd model the round parts of the cube to match the cylinder so the shape is perfect. Then add edgeloops and smooth.
I think maybe 12 sides for the cylinder would do the trick.
I currently have no Maya with me so I cant test this out, but I think this would work. Let me know if you need more clarification to this.