Most posted job positions in the US, that I see, explicitly state they will not sponser candidates. But how receptive are they to TN visa candidates and do you see that attitude changing in the near future?
That's mostly a knee-jerk ignorant position since it's oftentimes very easy, fast, and inexpensive to hire a Canadian in TN status. So it's a process of somehow getting through to someone at the company to educate them not to pass on a good candidate simply because they're Canadian. Which of course is a lot easier said than done.
Does this also apply to Mexican's wanting to get a TN as well, I've heard the process is slightly different?
It's a different process for Mexicans because they're not visa exempt like Canadians and so have to get a TN visa at a U.S. Consulate.
Would emigrating to Canada be a viable path for European citizens to eventually get a US work visa? If so, would it also be a path towards a green card?
The law firm I work for (as lead software engineer) did the TN thing for a Canadian software engineer hire for my team last year. [I was not involved in the paperwork but] my understanding is we got an immigration lawyer to help us write everything the right way, since we had not done it before (and lawyers specialize), and it was not especially expensive and it all worked out quite quickly.