We have developed a product based on the USBizi and used Panda II boards to develop it. We also took the Panda II and deleted several unneeded things and added other stuff that the design requires. So, in the end, if you were to look at the schematics, some blocks from the original Panda II are easily recognizable (i.e. USB, reset button, and so on), but the thing as a whole is very different. For the moment, the company has no plans to share the schematics of that design.
From what we understand, all this is fine with the license terms (CC BY 3.0 (http://creativecommons.org/licenses/by/3.0/). The sticky point is on the attribution. The license leaves that to the original authors (GHI) and we want to get it right. My question is, what are the attribution terms required by GHI. Since the schematics are not public, do you want something on the silkscreen or in the documentation? Or both? Is there a specific verbiage you require?
I think the same questions apply to the software, since it includes assemblies exclusive of GHI. Is that part covered by the CC license or the Apache 2.0 (http://www.apache.org/licenses/LICENSE-2.0.html) or a different one? What are your attribution requirements in that case?