Fatdog is an all 64bit version of Linux built from source packages and using Puppy Linux scripts and structure. Fatdog is quite 'fat' compaired to Puppy, the complete Xorg is included along with other extras that make it larger than Puppy. Other differences include Firefox, Xine-ui, Thunderbird, and Pidgen running as a non-priviliged user (spot), automatic Xorg configuration, default localization (see the setup wizards to make adjustments). You'll find CUPS in your browser's bookmarks if you want to add a printer.
For more information see, homepage and Fatdog wiki

Download and use appropriate installation method.
Download page

Fatdog64 521 thread
Fatdog64 520 thread

Promotion video
Screenshots video
Secure use of the non-root spot directory

64bit and Multi-core Puppy Versions wiki
FatDAW - Fatdog Digital Audio Workstation