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.

Monster used to have a model banana plug called the Exterminator that had a hole on its rear to piggyback another banana plug.I still have some,but they aren't for sale.

You can stack most banana plugs. Check out Parts Express.
https://www.parts-express.com/parts-express-gold-dual-banana-plug-black--091-334

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.