Select existing layers to build a map

When creating a new Map Context, it would be great if you could pick from layers already known in the system. A flow like this would be great:

- Pick layer, like you know pick a service
- Preview
- The projection & extent of this layer are copied into the properties of the Map
- Additional layers can now be selected, using the same cool widget as is now used for the service.
- While the map is shown in edit mode, the map itself can be used to select an new Extent by zooming to the required zoomlevel, and updating the extent x&y with the press of a button.
- When the map is shown in View Mode, a list of Layers that is used to build he map is presented as links to their layers pages.

While i am at it:

- While searching for Layers, users could add layers they find interesting to a 'shopping card' (displayed in a block)
- When done shopping, they checkout, and immediatly create a Map Context with the selected layers.

did i mention i already think the module is way cool?
groeten, reinier