This is pretty slim evidence, but still interesting. As you might expect, people have gotten to datamining the PTR client by now, and along with all sorts of interesting graphics, they've found some interesting categorization. To be specific, there are now assets (which I think just means bits of data) categorized under "Expansion02" and then under "howlingfjord." Why is this interesting? Well, Howling Fjord is an area in South-Eastern Northrend!
It has long been speculated that Northrend is going to be the area of a future expansion, what with Arthas and all that lovely lore stuff. It's also very conspicuously missing from our Azeroth maps. According to WoWWiki, Valgarde, an outpost in the Howling Fjord, "has since become the center of Alliance activity on Northrend." So that makes Howling Fjord a pretty likely Alliance starting zone for Northrend. On the other hand, Blizz have said that we're a few expansions away from being able to defeat Arthas (but that doesn't necessarily mean they won't open Northrend and just keep Arthas from us).
What do you think? Is "howlingfjord" being categorized under "Expansion02" anything we can draw conclusions from?