stevesaliman/gradle-playground — pull request #1 by Vampire (2014-05-13 07:17:21+00:00)
Title: add some debug messages

Actually I wonder right now why the brother project is not added if you run from master.
But besides that, changing the rootProject directory does NOT work from your example.
Of course the property value of that object you changed did change.
But pull in this request and let it run again and you will see which build files are really evaluated.