I got answer back from Mr. Gisske.
The Waldlaufer in 20/76 and .22 WMR would be 5,000 euros. I need more details before commiting...
Now I don't know if I should get the 20 ga with the .22 WMR or my dream of 28 ga with a .22lr? Or maybe both. They can fit a second set of barrels to the same action.
What do you think?