Tile Renderer exists because I wanted to be able to render an image at many times the pixel resolution (DPI) that my machine could handle in one go. I used a tile renderer (also called a region renderer) in college to output high DPI images for exhibition size renders on the banner printer.
Here is the Tile Renderer and the Automatic Stitcher (to remove another portion of the manual labour). Automatic stitcher requires PIL and subsequently needs a python version for which a PIL distribution exists. (2.6 & 3.1 is what I use). The Tile Renderer runs happily in Blender 2.5x which uses py 3.2.