Just my thoughts, because I believe that the concept is technically sound, in that such a mount could be solidly attached as you describe. Smaller, shock-resistant opticals, such as the Docter sight, already mount to the dovetail.
I don't think optics such as the Aimpoint tube, Pro Point, etc., would stand up too well or work as well, if mounted directly to a rail attached to the slide. Come to think of it, the only secure method I could think for the front of the rail would be to use a threaded tenon, such as are used on Heinie's, etc. However, how would you install the rail with a tenon protruding from the bottom front of the rail?