That looks very good on paper as it fits in arguably our 11 best players and leaves out the weak link at left back. I couldn't see it working in real life though (probably with the exception of San Marino). A 3-5-1 is just another version of the 5-3-1 with your full backs playing in a more attacking role. Duff and McGeady aren't full backs. Maybe Duff could play the wing back role but your sacrifising him taking on players.
I don't know. I think if we had this thread after the last Swiss game almost everyone would have Harte at left back. He was playing very well under Kerr.
http://foot.ie/showthread.php?t=30179
^^ A lot of them use his set pieces as the reason to have him in the team but he was very sound defensively for us at that time too. Actually, I think you'll find the last post in that thread very interesting... :D