> isn't tomorrow always pronounced to-more-row

Errrr, no. Though my written form may be unclear to you.

The pronunciation of this word and others like it (e.g. 'bore-row' for borrow) is a 'secret' way to tell Canadians and USn's from one another. This vowel sound is the main difference between the two accents, but not the only. In ordinary language you don't have to wait too long before being able to confirm from which side of the border the person comes through this. Most of the time I can quickly single a suspect North American accent, I then wait for the 'to-more-row' confirmation - or alternatively an 'eh' at the end of a sentence before breaking open the maple syrup;-)