He wasn't asking for two Command Nodes, he was trying to work around the issue of a 4x4 node having no center point. Saying that either the center could be a 2x2 block in itself, or that perhaps you can pick one of the four center blocks to serve as the fake "center". Though that last I feel would throw off a few things and cause more problems than it helped.
As a quick way around the problem of symmetry, I've seen a few ships that use another 3x3 block to "balance out" the Command Node, usually a tank, guppy, or port module. And you can expand that out to a 2x2 square of 3x3 modules (difficult to follow, I know) if you had a mind to. Meaning, one Command Node and 3 other modules all in a square. It's not perfect, but it might help you for the time being.