The Shadow was widescreen on Laserdisc, (It also was the first DTS LD!) as is the UK DVD. But whether it's at the proper aspect ratio seems to be in doubt.
http://www.dvdbeaver.com/film/DVDCompare/shadow.htm
I'm surprised this didn't pop up on HD-DVD as Universal was redoing a lot of their old catalog titles up until the plug was pulled.