This app supports reparenting of user stories and updates the requirement type appropriately defined by the user's preference if it exists. Otherwise it will default to the requirement types defined on user story. A custom field with a display name of "Requirement Type", a name of "RequirementType", and of type drop down list is required for this app.
See a screencast here: http://www.screencast.com/t/BA5NxLcBpa
If you want to grab the App and try it you can find it [here] (https://github.com/RallyCommunity/RequirementsHierarchyTree/blob/master/deploy/App.html).
Requirements Hierarchy Tree is released under the MIT license. See the file LICENSE for the full text.