How to create a summary report that contains other reports?
You can do this.  You can create a single report that has multiple data sources (one per environment).  Add the data sets required.  Recreate the graphs (you may be able to leverage some cut-and-paste).  In order to format them nicely, you will need to place the graphs into the cells of a matrix. 

You could also build a single report that links to other reports.

I realize this is a high-level description of how to do it - if you need further details, let me know.