I went through the database list of the PAL xbox360. Correct me if i'm wrong but these are missing:
Avatar The game Collector's edition:
http://www.game.co.uk/Games/Xbox-360...4666/?s=avatar
Need for Speed: Shift Special Edition:
http://www.game.co.uk/Games/Xbox-360...42610/?s=shift
Far Cry 2 Steelbook:
http://cgi.ebay.co.uk/Far-Cry-2-Limi...item3a5a7a7bd5
Prince of Persia Steelbook:
http://cgi.ebay.co.uk/XBox-360-Princ...item335cbdbced