The problem with 17" is that if there is an update of SR and LED displays for the 15", there are no 17" LED panels yet, so it would be one spec behind...
I'm not trying to say you are wrong, but are sure there are no 17" LED displays? I ask b/c of the significant absence of people complaining about such a situation, which if you look at any thread in our beloved forum, tends to be what we love to do so the lack of such a gripe seems odd.