+1.
Reading your post has brought hope this may be a reality for the F3x range.
Have looked up the part number you mention, 7849406, for the buttons and found a seller in Lithuania who can do a complete new button module with M1 & M2 buttons on the left module where many people have blanks.
https://vinicart.com/products/new-bm...ontrol-buttons
Would like to know whether you would be willing to produce some kits of your project?