@PostgreSQL: Might I ask if this is still being actively considered or should we repost to another mailing list (perhaps pgsql-hackers or any other you might suggest)?
This is the right place for such a discussion. Unless you think you've come up with a design that you want to propose and that, if accepted, you would then write up a patch for. For that you'd probably want to move the discussion to -hackers with an outline of the patch you plan to write.