Both the Oppo and Cambridge are based off the new Mediatek SDK, a standardized product for high end blu-ray capabilities using advanced video scaler called the Marvell QDEO.
Mediatek license this design out to smaller firms so they do not have to reinvent the wheel by designing a new player from the ground up. Yes, this includes Oppo. PCB layout, rear ports, firmware and such is very similar, because they stick to the reference design.
Where they differ vastly is on the audio side. The 751BD essentially has the latest DacMagic built in for audio, while the Oppo-95 uses a Sabre DAC.
What Ayre and other manufacturers do is something totally different. They physically buy the Oppo players, then strip out the boards and mod them to make their own product.