Well, I tried the 'hot box' method on my PS3 brick last night and it worked! Basically, wrapped the PS3 in a large towel then took my wife's hair dryer, put it on the back of the PS3 for 10 mins (by the HDMI input where the heatsinks are) and then cooled it down with a fan for another 15. Plugged it back in, connected the HDMI and presto!....my GT5 disk ejected and the YLOD was gone. Was able to get on and backup all my saves, etc (thank god) and transfer to my new slim.
This is only a temporary fix from what I have read...the solder softened enough to restore the contact points on the board, but it will degrade again in time (anywhere from a couple of days to several months down the line). So now I have a backwards compatible PS3 to use as backup/for PS2 games at need.
If anyone has the YLOD and wants to try this partial fix...just search for 'PS3 YLOD hair dryer' on the tubes and you will find several examples of how to fry your brick back to life. Just know that applying hot air to any electronic device is generally not a good idea, only do in case of emergency or withdrawal.
Cheers for now.