Guys, "it" exists:
Product: Shimano Cable Housing Junction Ferrule, 5.0mm I.D., Each ID#: BPC317324
In the image you can see a slight protusion surrounding the tube just below the midsection. I saw that and decided to take a chance and order a couple from Bikeparts.com. When they arrived, I opened the package and to my delight, they are indeed double-sided! Unfortunately at $3.99 ea they may seem prohibitive for a lot of applications, but for that special situation every now and then it seems completely reasonable to use these.
I knew there had to be such a thing.
Thanks to those with helpful input and to the doubters and haters, well...
(in a light-hearted, childish fashion mind you)