Steve,

The first line of automation there is to use the Dashboard templates that are used to instantiate the initial dashboards for each team that is defined in the Process Template (Project Configuration>Configuration Data>Dashboard>Dashboard Templates).

If you need to programatically update or create new ones, I don't have direct experience with that but the Dashboard team does have some information on the wiki that exposes some APIs for access and potentially creating them.
https://jazz.net/wiki/bin/view/Main/DashboardServiceAPI

-Sean

Here are some docs on how to create dashboard templates, which are used to provide defaults for team and project dashboards:

http://publib.boulder.ibm.com/infocenter/rtc/v2r0m0/index.jsp?topic=/com.ibm.team.dashboard.doc/topics/t_config_dashboard_templates.html

The dashboard templates also part of the process templates, e.g. scrum, openup, etc. So if you want every project and/or team to get the same initial default dashboard, you might want to create your own process template and use that for all the new projects.

Note that the dashboard API link mentioned above is only available in 3.0.1, so you won't be able to use it until it's released and you upgrade (https://jazz.net/wiki/bin/view/Main/DashboardServiceAPI)