Untyped result (setof / rowset) from Functions ?

Is there a technical reason why an untyped result (setof / rowset) from a
function (sql or plpgsql) is not implemented ?

Something Simple:

CREATE FUNCTION foo(x int) RETURNS SETOF records AS
'SELECT t1.*, t2.* FROM t1 INNER JOIN t2 ON t1.a=t2a
WHERE WHERE t1.id=$1'
LANGUAGE SQL

So I will not have to create a TYPE every time I return a SETOF JOINED
tables or a sub-set of the columns of a table.

Thanks.