For some reason I again attempted to use the portal on my DK, about an hour ago. To my surprise it worked! It seems you can experience the MoP 10-day free trial atleast twice. Whether or not this is meant to be the case or it's a glitch I don't know.
Unfortunately, my two level 85s have reached the experience cap so I'm just going to use them to farm up some more fruit and veg until my actual copy of MoP arrives in the week.
Below are some screenshots...
|Shrine of Remembrance.
|Bridge over the Yan-Zhe River, between the Jade Forest and Valley of the Four Winds.
You may be able to see that my Mekgineer's Chopper went all silver for a brief time.
|Mid-flight on a kite.
This image is from a while ago, when I was taking my shaman through the Pandaren starting area. You may recognise it from my blog home page. I'm including it here to geotag it so will now appear on my WyriMap.
|The Giant Carrot!