Install drupal without node module?
The node module is marked as

required = TRUE


in the node.info file, so the developers are basically saying that as far as they're concerned the node module is imperative for Drupal 7 to function correctly.

You could try patching the info file to remove that line, then disabling the node module to see what happens...in fact if you do that you should write a blog post about it or something, it would be very interesting to find out the effects; I've never heard of anyone trying to do this before :)