If you are interested in an Altium version, there is a version for the original A5B board they can be found at Altium A5B. These files are provided AS IS with no support.
If you are interested in an Mentor version of the A5C board they can be found at Mentor A5C. These files are provided AS IS with no support.
Mentor has also recently released a PADS version of the board at PADS BeagleBone Black.
You can find the Solid Works and 3D PDF files provided AS-IS at 3D Models