I personally find that 16 rogues are probably the only viable "scale twinks". The reason I think this is because they are the only class which survivability is irrelevant. Stay stealthed, do your nasty deeds, re-stealth. I have a 16 rogue in my sig which I barely play.
Although I know scaling was different in Cata, when I played him it was great fun.
I find that Belfs are the ideal races for rogues to lock down their opener.