I'm looking for a solution similar to the WordPress widgets page or the iGoogle page. You basically have a main dashboard with a pre-defined selection of portlets and then a menu down the side/top with available portlets.
You can move portlets between the dashboard (where they will be fully expanded) or the menu (where you just get a title). A portlet would only be able to be in one or the other - not both.
Any advice/links?
Give jQuery UI a try. It requires some configuration but provides all functions necessary for what you want to achieve.
http://jqueryui.com/demos/droppable/#revert
http://jqueryui.com/demos/droppable/#photo-manager