I am likely to get an offer of employment in the US and my employer says that I should be fine on a TN status. Now I know that the TN status is renewable with no limit. I also know from an immigration related message board that quite a good number of people are in fact using that clause and have been working for 8 or 9 years on TN.
What I don’t understand is how does it work? Doesn’t the service center or the border officials object to renewals when they see that the person appears every year with a letter from the same employer saying that the job is not going to last more than an year?
What do you mean by Tennessee status?
Well, my fav Memphis bar, Platinum Plus, was recently closed down due to prostitution and drug dealing, so that might factor per your query, though I did recognize its furniture in Christie’s Cabaret, so there might be a resurgence/rebirth thereof, FWIW, ye wank. 
You might also take a look at youtube and search for “Cohen and Grigsby.” The future of immigration might be changing in this country.
I worked briefly in the US under a TN visa (for the confused, go here). Although it wasn’t long enough to get renewed, the impression that I got was that they didn’t actually care about how many times you renewed it, as long as you followed the guideline of leaving and coming back at least once a year.