You can remove the country code from the URL, so it reads
http://itunes.apple.com/artist/nash-the-slash/id160526527. That gives you a valid iTunes URL, that if opened in a browser (that doesn't auto-open iTunes), appears to be the same as if the link were a US link.
However when any iTunes link is opened in iTunes itself, it will attempt to redirect to the version in the user's local store. I.e. when I click on the link you posted, I get sent to the same item in the Canadian store.
If the item isn't available in the Canadian store, I get a message like this:
So, you should be safe using country-specific store links, and iTunes will handle the redirection as appropriate.