Why 1000 and not 1200? Just because it's a rounder number?
maybe but mainly it is because selling is mostly a mentality thing
looking around i keep seeing people waiting for the $1000 and praying to the old gods and the new! to see that price and start dumping.
that is why to your main question i say most probably there will be a big resistance starting from $1000 specially if it happens in a short while (not if it happens after a couple of months!!)