Highlighting Sparse Tree Leaves

[Wanrong Lin <wanrong.lin@gmail.com>]

Hi,

Is it possible to highlighting only the sparse tree leaves, or even 
better, highlighting the whole sparse tree but with leaves in a special 
face?

The motivation for such a feature is this:

Suppose I have a task tree like this:

* TODO Task A
*** TODO Task A.1
***** TODO Task A.1.1
* TODO Task B
*** TODO Task B.1
***** TODO Task B.1.1
***** TODO Task B.1.2

If I do a "org-sparse-tree", all those lines are highlighted, giving an 
impression that I have a lot of open tasks, but in reality I only have 
three tasks: A.1.1, B.1.1 and B.1.2, as the higher level tasks are 
automatically done if those are done. So it would be nice to highlight 
those leaves in a special face. Also, suppose both B.1.1 and B.1.2 are 
done, then Task B.1 should be highlighted as a leaf.

Hope the above makes some sense. Thank you very much for giving it a 
thought.

Wanrong