Hey RAT, I know that a lot of blokes report requesting a new level 'due turbulence' to help ATC develop a picture of what the day is like for following traffic. I know I use it if it is the reason for the level change but have to say that I never expect a 'priority' because of it. Maybe ATC will hurry the request along a bit quicker because of that but that would be entirely dependant on the controller I guess.
And to actually answer your question, I haven't heard of such a reference in the Jepps either.