Wow, I just got here! I am new to Evernote, and I was disappointed in only being able to create a two, or three, level hierarchy of note books. The ambition that you are referring to is called "classification," and I have been working on such systems for the past twelve years. In general, the library classification systems fail to meet our expectations for implementing them into our computer directory filings and application notation systems, such as Evernote.
If Evernote has a principle for "reflecting reality," then I need to check that out.
Anyway, to get to what you want, it is going to be a seven element subject system that covers all of reality efficiently, compared to the fifteen that the Dewey Decimal System has, and the 27 subjects that the Library of Congress classification system starts off with. Hopefully, I can provide more details later on.
Reality
Nature
Technology
Life
Society
Culture
Time
Personal
Relations
Activities
Health
Civil
Organizations
Property