I will be checking responses to this post because I would be interested in the same thing! I have been compiling a list of essential questions in Biology for my students. I haven't found any kind of comprehensive list of key ideas which I why I have been forced to create my own. My list is a work in progress and I am constantly revising and improving.
Our state of NJ has been working with Grant Wiggins from Authentic Education, Hopewell, NJ, on a standards clarification project that addresses essential questions for the different subject areas. Here's the link to the project website which also includes a training video on essential questions. This may help - I'm using it for faculty pd too.
Could the PD be designed around staff developing the questions themselves? Might get more buy in this way and the transfer of learning from workshop to classroom might be more successful. Speaking from a teacher's perspective here.
I don't know if this is what you want (maybe too narrow) but last spring we did a unit of study on the Titanic which started with the question "What to the primary sources tell us about this tragedy?" You can see our work here.