If you take the plunge digitally, you'll still get the design booklet.
Super Mario Maker is now up on the Wii U eShop for digital preload, and a new option has become available for those who want the booklet that comes with physical copies.
After prebuying the game - note payment of the $59.99 (US)/$69.99 (Canadian) +tax upfront would be required - a toll free number will be given on the eShop receipt. Calling the number and providing your name, address and system serial number will have a copy of the booklet shipped to you.
A PDF version of the book will be available on the Super Mario Maker website from launch day.