I would like to be able to trigger a deployment to a particular environment once one of my stages has been completed.

My goal is to create different deploy environments, each with separate permissions, some tied to fully automated build plan stages and others tied to manual stages of the same build plan.

I can see a few reasons for this:

1. You want to isolate the 'deployment' tasks from the 'build' tasks. If my deployment to prod fails due to, say, a connectivity issue, that doesn't mean I need to rebuild my binary. Just re-running a deployment should be fine.
2. Tag creation and artifact promotion (to name 2) do not belong to deployment. I want to be able to re-run my deployments, roll them back, etc. How should I address the tag creation if I put this task in a deployment environment? Think of re-running deployments, roll-backs, etc.
3. I still want to have as much as possible automated, hence I want to deploy to my ENV: Test as soon as I have a green build. I do not want my developers to have to manually create and deploy a release.

Found the following related tickets:

BAM-13347 - Represent deployment triggers as stages within a plan OPEN
BAM-13501 - Authenticate to see issue details

And also logged this question in Atlassian answers:
https://answers.atlassian.com/questions/11441200/bamboo-deployment-how-to-trigger-it-without-completing-all-stages