My left foot is also slightly smaller than my right, although not by an entire size. Maybe a quarter-size, or a half-size at most. When I buy regular shoes, I make sure the right is comfortable, and then the left is usually OK, if not quite perfect. With things like snowboard boots or ice skates, however, I try both on, then make a judgment based on the way the set fits. Having the right just a little bit too snug is better than having the left too loose. Fortunately, boots tend to pack out, so in my case the slight discrepancy usually can be overcome by differential packing. That might not work for a full size.
You may want to try a separate pair of heat-moldable liners. That should give you a custom fit for each foot. Use a toe cap on the right if it needs more room.
Last edited by JoeR; 01-14-2011 at 02:02 PM.