Don't think they will do this until next year. The reason i am saying next year is because DK start at 55 and Blizzard wants you to get use to the DK by the time that you are 80. If you speed 55-70 you wont have that much knowledge of your DK.

Hell i have a lvl 68 priest that i have no clue how to play. I have to keys bind to her smite and greater healing. I power lvled her to lvl 60, and now have her grouped with my DK. Well the good thing is that when i group with people i can be like well i was a dps before so this is my first time healing or i was healing spec before so this is my first time dpsing.