The problem is the copyright:
"Design (c) 2011, 2012 Raspberry Pi Foundation
All Rights Reserved"
As far as I know the schematics are not open-source, i.e. there's no right to use them other than as documentation for the (proprietary) Raspberry Pi-manufactured board. The BeagleBone, on the other hand, has an open-source license for their schematic under Creative Commons Attribution-Share Alike 3.0 Unported License.
> http://elinux.org/RPi_Hardware#Schematic_.2F_Layout
> http://www.raspberrypi.org/model-b-revision-2-0-schematics/