James Wellbelove and Burns is now being sold in Canada at speciality pet stores, I understand they are quality foods though I have not checked out the ingredients.

Others that suggested food may not be that far off, check for common ingredients in all 3 foods you have tried, in my one greyhound Sunny's case he cannot tolerate corn, it will cause him to vomit and cause loose stools.

Another possibility which can cause ocassionally vomitting is empty stomach symdrome, often you will know if this is the case as the vomitting is mostly occuring in the mornings, it can be helped by feeding 2 meals a day instead of one and also giving them a bedtime snack like bread or toast, so they are not going long periods without food in their stomach.