Saw several generic ones and am thinking about putting one in and was wondering if anyone has ever installed one. That is onething I would dearly love to have.

Me too, but so far I have not found one that looks nice/original or can be hidden, therefor I am waiting and looking for a suitable one.

Cool idea... my immediate concern is how well the projection would work given how sharply raked our windshields are.

I had one in my vette and it is raked about the same and it was fine and as far as hiding it, was thinking about putting it between the dash cap and the dashboard. That way the display could be angled to show low on the window.
The unit that projects the speed is on 3" x 1", that is the size of the one I am interested in. Going to do it when I get my dashboard recovered, will let you know how it comes out.