Just noticed an ad yesterday for Adwords itself where the destination domain is different to the display domain.
The display URL is adwords.com.au but destination is adwords.com/blahblahblah
The funny thing is they even quote, almost this very example on their policy page:
Display URL: google.com
Landing page: google.com.au
These domains do not match because one includes the country-specific category ".com.au" while the other uses ".com."