Planner/optimizer tool

I'm scoping a project to display the choices and plans the 
planner/optimizer considers while PostgreSQL develops a plan.  It would 
be primarily a teaching tool but may be of use to users curious about 
the inner workings of the planner. 

This is in contrast with EXPLAIN, which provides information about the 
*final* plan selected by the planner.   This tool would show details 
about the access methods available at each step and the associated 
access costs, for example.

There is a TODO item: "Allow EXPLAIN output to be more easily processed 
by scripts, perhaps XML" which could be a good first step for this 
project. 

Is anyone working on a related project?

-Tom Raney