MFJ has such a vast selection of such cables off-the-shelf and at low prices, that I can't imagine anyone could easily compete.
If you go to MFJ's website http://www.mfjenterprises.com
, click on the on-line catalog, and then click on "cables," you'll see a very long list of interseries cables for connecting almost anything to almost anything amateur radio related, including all the popular mike and accessory plug configurations for rigs and accessories. They're all pre-made, and they're inexpensive.
They seem to stock all of them (or at least any time I asked, they had it).