Hi, Ian!
You can find a discussion of Rotation Model with intergenerational groups here: Discussions: Preteens in Rotation, Intergenerational Rotation, and Spiritual Development.
You can find specific lessons and programs people have developed using the search function and the term "intergenerational."
Here is a Wednesday program that @Luanne Payne was planning: What's In The Bible? Intergenerational Weeknight / Summer Ideas & Resources.
I believe @Beth Tobin has some experience with churchwide rotation model classes.
And this is an idea you might be able to incorporate: The Faith Mentor ~ Family ~ Intergenerational Workshop Concept.