Teachers of K-12 social studies, if you have not already checked out the Inquiry Design Model website you really should.
They have collected and vetted inquiry units from around the country for all grade levels and all traditional social studies subjects.
Even if you don’t find something you can use as is, they allow you to download Word versions that you can edit as you see fit.
In addition, they have a nifty inquiry generator tool that will walk you through creating a custom inquire task.
To access all of the content and features of the website a simple and free registration is required.