CPPersistentDefaults is a utility class by Adam Knight of codepoetry (http://www.codepoetry.net/) that emulates NSUserDefaults, but stores all values in a Core Data Managed Object Context instead, thus allowing for easy per-document settings and preferences.

It is available on the site under an MIT License (aka BSD-style): http://www.codepoetry.net/2006/07/24/cppersistentdefaults