Sorry, but you are bit late, by about 90 years. Here is a page from a 1930 catalog, showing small bore over – under combinations. These were available then in 24, 28 and 32 = .410 gauge in the shot barrel and 5.6x35R Vierling = .22 Winchester cf, 6.5x52R = .25-35 and some forgotten other German smallbores. Sorry, but I have never seen such a thing during the last 55 years. Today, the Ferlach gunmakers will be happy to build such a gun on order. But if you have to ask for the price, you can't afford it anyhow.