Yes, there are! Roticity is one interesting example of how accents and pronunciations can vary. I remember once seeing a video where someone from the UK answered the question, presumably sent in by an American, of why they didn't pronounce the "R" at the ends of words, and they didn't think of it as not pronouncing it.
The "wh" thing is interesting. I've noticed that certain American accents pronounce the "H" right after the "W" in "white," but I've always thought of it as a silent "H," everyone I know pronounces it more like "wite."
I think with the "mc" or "mac" thing, I would naturally clip the vowel.
And I just remembered another name - Graham. Some people pronounce it more like "gram" and others like "grame." I get that when it's a person's name, it's more likely to be the latter, but I feel that when I was introduced to graham crackers, it was the former, but my mum says the latter.

Oh yeah, I forgot about the spelling "Graeme."

Interesting theory!

Phonics help!