I know there were a million ways to speed things up but using ALL the elements of the sky i wanted, with +1 quality settings, and broadcast my 24x18 inch render took 278 hours. I have lots of computers and the render farm wasn't available as I was updating it for Poserpro 2010 and Carrera 8 beta, all it kept me from doing was using Vue. I was hospitalized for 5 of those days so no worries.
The bottom line is I love 30 minute renders, but can you print them in large format and still love how they look, maybe but i prefer to wait.