Options to make the Filter Pane more customizable

It would be nice if the Filter Pane was more customizable:

1. There should be an option to add sub columns within the main columns in the Filter Pane so that the lists in the filter lists could be sorted by other strings than the filter string. That way, us geeks who care could sort the Album filter list chronologically.

Visualized:
|| Genre || Artist || Album || < Today
|| Genre || Artist || Album | Year ^ || < Filter Pane with "sub columns".

You can also look at how Winamp does this while in the Audio section of the Media Library.

2. Related to this: It would be nice to be able to choose how many filter columns are shown in the Filter Pane. For some people 1 filter column is sufficient, while others might want to filter their List by 5 or perhaps 10 parameters.