From the CM10 thread, those who have SOD/Power Button issue.
Symptom: Recurring SOD, power button doesn't respond.
Solution: Pressing the back of the device near the camera then pressing power button.
Started: In the advent of ICS (beginning from KU5900 firmware)
This is your problem.
Opening the device, you will see several gray foam like on the underside of the back-plate for each small part. Might be wear and heat that these foam like doesn't put pressure anymore.
If this is soldered or snap on, it means it loses contact. That's why pressing the back of the device works.
What I did was open the device. On that specific part there are
two things that presses it on the underside of the back plate.
A gray foam like, and a black rubber like just above the gray one.
What I did was
remove the black one, and put it on top of the gray one on its top edge. So the press is more effective. Screwed the back plate and assembled again. Waking the deice hereon never failed.