Coupling Banana Plugs

Well I think I can answer my own question.
I just purchased a couple of banana jacks that are designed to go into a in wall type box.
One side accepts a banana and the other side is designed for bare wire , but it can accept a banana. That side has a set screw for the bare wire but it can also be used for tightening and locking the banana in place. I cut out the plastic that surrounds it.
Looks pretty cool and functions perfectly.

Yes, but the cables I am using already have banana's attached on each end. So stacking is not an option.

What I seek is a coupler. Sort of like a RCA coupler that is used to connect 2 RCA's together, but made for banana's.

My DIY version does fit the bill, but I am surprised that there really is no commercially made product.

Thanks Al, The one highlighted in yellow is what my DIY looks like.
It seems all that would work on the image link that you have provided is either in China or the UK. Nothing in the USA.

Good point. I used some clear thick spiral wrap around the metal.

Zd542, Swampwalker, thank you for your comments.
I had about 25 feet of Kimber 8TC and found another 18 footer used. This second set replaced a cheaper 20 foot pair.
With the cable now all the same, I found that it did increase the output and the sound quality.