COPY IN as SELECT target

Recently there was discussion about allowing a COPY statement to be a 
SELECT target, returning a text array, although the syntax wasn't really 
nailed down that I recall. I was thinking that  we might have
   COPY RETURNING ARRAY FROM ...

instead of
   COPY tablename opt_column_list FROM ...


the we possibly could do things like:
   SELECT t[5] as a, 3*(t[3]::numeric) as b FROM (COPY RETURNING ARRAY 
FROM STDIN CSV) as t;

Thoughts?

cheers

andrew