Over the years, there have been occasional requests for such an adapter. The typical use is to adapt the Leitz Vario Orthomat zoom lens, p/n 543431 to T-mount. An eBay seller in China has done a custom run of these at my request.
You may reach him on eBay as seller "amoyca2011". Delivery was timely and the price reasonable. The material is black anodized aluminum.
I would show a picture of the adapter in use, but I do not have the zoom lens. I use it for an entirely different purpose that readers of this forum are unlikely to have.
I have attached pics of such a lens that I sold on eBay last year. I checked the fit on another Leitz part threaded M45 that users are unlikely to encounter.
Images made through a microscope. All subject types.