I hope this is not too late. I had this problem, and I followed the steps outlined in your email, but I could not reset the SMC because the battery was drained. My daughter took the Mac to the Apple Store because the logic board was less than a year old, the the battery less than four months. She was told that it was a logic board problem, and that the solution was around $300.00 - but they gave her a new battery. She brought the Mac back to me With the new battery, I was able to reset the SMC, and all is now well.
Mac Book Pro 2008.
This is going to seem crazy, but after reading lots of these threads and no one coming up with an answer, I picked up the ball where it was dropped and tried something.. different. Some people had some luck replacing the battery connector / contact, but it only worked intermittently. My belief was that perhaps the computer body was simply warping and causing the battery disconnection. I then applied a vice clamp to the part of the body that houses the battery and the connector, slowly increasing the pressure until, Presto! The macbook started up.
While it's not a permanent fix, it does work now, and it's illuminated what the problem is.