I would like to suggest that you add a "Build Tag" feature to FB in order to control if an action is to be executed or not in a build.
At the Project level you should be able to define a number of tags such as "Release build", "Q&A build", "With codesigning", "Feature 1", "Feature 2" etc.
For each action there should be a list box with all the Build Tags where you can check each of the tags that would cause the action to be executed. Probably on the Runtime tab.
I know that you can do the same using variables and Execute conditions or scripting but this quickly becomes "messy". I think a Build Tag feature would make it much simpler and would eliminate a lot of boolean variables from many users scripts..
We have had a feature on the drawing board for some time which is almost exactly as you described it. It's just a case of finding the time to implement it. I'll talk to the team about it again today.
Just had a discussion with the team, unfortunately there is not enough time to get build tags done and tested for 6.0, however it is now feature #1 for a 6.x when time permits (we'll start work on it pretty soon after 6.0 ships). We also managed to come up with some pretty cool things we can do with this feature, hopefully it will be worth the wait :)