well as for 33 RPM album stitching can be done with the free program "Image Composite Editor" from and only available for windows.

As I have a A4 scanner that would made me 4 scans from one side then stiched together and that work very well for me.

Auto-Focus is not something I have seen on scanners (yet) and to buy a A3 scanner that would cost me too much money for the little collection albums I've got (Few Hundreds)

I'll stick with my A4 scanner for now and my method of scanning 78's .. if any of you got different idea's for scanning 78's or whatever piece of music feel free to comment