There have been a number of postings about having a Cocoa document based application where the documents are packages. None of the posts seemed to nail exactly what I wanted, so I managed to piece together a bunch of posts and came up with some sample code to demonstrate it. I used this as a basis for ReceiptWallet 2.0, but have made a bunch of changes since then. Feel free to use this code in any way you see fit, but I make no promises of how well it will work for anyone besides me.