UPDATE tuples with a sub-select

Hi,

are there any plans to support updating a tuple using a sub-select in one of the future versions.

e.g, something like:

UPDATE report_table
   SET (order_count,order_value) = (SELECT count(*), sum(amount)
                                    FROM order o
                                    WHERE o.customer_id = report_table.customer_id);

I know it's currently not possible (so we need to revert to two sub-selects) but I was wondering if this somewhere on
the"roadmap" 

Regards
Thomas