Is there any way to render the thing in sections?
I suppose you could render the file in smaller avi segments. Just adjust the start and end frames on the Animation section of the Scenes panel. However, I suspect they would not go back together seamlessly. But I haven't tried it. Of course, you would have to make each file name unique to prevent overwriting the previously rendered section.
Serious animators render their output as a series of still frames and re-assemble them in editing or compositing software. Blender allows you to output in this manner. For example, simply change the file format to save the output to JPEG. Blender will save a series of numbered still files instead of an avi movie. The filename of each jpeg will be the same except for the end which will have 0001.jpg for the first file and 0650.jpg for the last if you render frames 1 through 650.
The advantage of this method is that a power failure or re-boot after 14 hours of rendering isn't a disaster. Just restart again and begin with the next frame you need. I made my intro this way and I suspect it takes about the same amount of time as putting it straight to avi.
Of course, you must have a program that can assemble a movie from a series of stills. I have an older version of Adobe Premiere and it does that easily. Simply load the first jpg in the file series and check a box that says 'numbered stills.' It loads all the stills and acts just like it loaded an avi file.
I think many editing programs can load files as a series of stills. You could test this technique out with just a few frames to see if it works for you.
If anyone is interested in how I made a 2.35 aspect ratio intro using a pretty convoluted method, let me know and I'll describe how I did it in this thread.