Want to find one and modify that to read, write file on mongoDB gridfs store
This tutorial will give you a good idea on how it was made: http://dailyjs.com/2010/11/01/node-tutorial/ As knowing how it was made it should make it heaps easer to extend it. :) It is quite basic, I'm re-writing the whole thing myself :P
Nodepad on github: https://github.com/alexyoung/nodepad
It even uses MongoDB, I'm going to do the opposite to what you wanted to do and that is make it not use MongoDB. :P