Mutable models based on dbfunctions or stored procs?

Is there any way that a model can be based on a stored procedure or
function that so that it can return a set of data based on a parameter
provided in either the controller, or s a variable in the model? That
way you could:

  1.  Set the variable
  2.  Call find_all
  3.  Get a mutable set of results that takes better advantage of some

of the advanced database features available?

There are many times when SQL code is simply a better way to twist and
turn data sets. (Olap transformations, speeding up joins in large
tables by using temp tables, etc.)