Take a look at the MKS pedals. The Touring pedals are about as wide as pedals get. The Grip King pedals are huge, real long from front to back but probably not what you want for touring. Velo-Orange also has their own pedals, similar to MKS but made by Wellgo. More expensive but kind of cool with sealed bearings. Check the websites for Velo-Orange, Rivendell and the big online retailers like AEBike and JensonUSA.