Xbox-scene.com forum posters believe they have spotted a 65nm CPU Xbox 360 in the wild - but without the use of the upcoming Falcon motherboard.
"The motherboard looks (almost) identical to the Zephyr, so I doubt it's the Falcon already. If the CPU is 65nm or not is hard to say ... it seems to be a bit different to those in the Pro-hdmi or Elite anyway. The smaller package, the lower power usage and missing 'power converters' on the right side of the board seems to indicate we indeed have a 65nm CPU here." read the posting.
No official word on whether Microsoft is indeed manufacturing 65nm components yet, but it's a strong possibility.