correct me if I'm wrong, but it looks like there are least three ratings from differing ratings boards denoted on region one USA DVD's. The MPAA, The Canadian rating's board and one I noticed on the back of the 'Wrong Turn 2' DVD that is a 16+ in a box - which one is that?

I was thinking maybe UK, but maybe not according to this google search result.
UK film ratings

Oh I know it's not the BBFC's rating, cause those are the number with a circle round them.

It's definately not BBFC - they never had figure 16 in their ratings. 16+ reminds my of Dutch ratings they have on their DVDs, but I found a picture of the back of Wrong Turn 2 cover and it doesn't look the same. Can you clarify what the letters beneath the "16" are?

It says "16" and "ANS +" below. I've never seen that type of rating before either.

"Ans" means "years" in French, as in "16 Years" (and up). It's probably for French-Canadian vewiers.

Quebec. As far as I understand, there's five major film boards in Canada - British Columbia, Manitoba, Ontario, Quebec (aka Regie) and Nova Scotia.

so, Quebec and what's the other more common rating that graces North American region 1 releases - Ontario?

The other one you are talking about is the rating for the Canadian Home Video Rating System thats used all across Canada.

http://en.wikipedia.org/wiki/Canadia..._rating_system
http://www.cmpda.ca/jsp/v-rating.jsp