My favorite example of "post-rationalization" is the BREATHTAKING Design Strategy behind the new Pepsi logo of the last decade.

http://www.goldennumber.net/wp-content/uploads/pepsi-arnell-...

The bit about Pepsi energy fields and globe dynamics is my favorite, but it is all kind of amazing.

Edit:

By comparison, this NeXT logo document seems pretty tame. Mostly describing the intent behind font choices and getting people's attention. Making the 'e' small does help prevent the all-caps design from looking like it has 'EXIT' in it.

And for what it's worth, I kind of like the NeXT logo. It looks a bit dated today, but it's not bad. Very 80s futurist.