customisable "overview" widget

it would be nice to have a customisable screen/dashboard widget in the style of overview. customisability :

adding individual items to a table;
deciding what to show upon mouseover for each item (could be several latest values, could be graph);
ability to show multiple items in single table cell (for example, show loads for all cpus individually, but use only single table cell for that to conserve the space).

inspiration : http://pawlowicz.name/MyServers