I usually render at 1280x1024 and print to my Epson 760 at fit to page (about 55%) via PhotoPaint. My prints on the heavyweight photopaper are beautiful (1440 dpi resolution). I have in the past rendered images at 3200x2550 (11x8.5 @ 300dpi) on the standard desktop (i.e. Not to disk) without any problems. It took about 12 to 18 hrs per image based upon the complexity/settings. How big do you have to go to hit that wall?

Pass no temptation lightly by, for one never knows when it may pass again!