returning a recordset from PLpg/SQL

Looking at the datatypes you can RETURN, it doesn't seem that there is a 
way to return a recordset

I tried
RETURNS SETOF RECORD
but that doesn't work

I even tried
RETURNS SETOF fooTable%ROWTYPE

What I would like to do is not that simple, I need to be able to 
build/declare a record definition with an arbitary list of columns and 
then return a set of that record which has it's values populated by 
queries and calculations inside the procedure.

returning an array is not a solution because I need to name all the 
columns and they will have different data types.