I haven't forgot my promise to post up pictures of the back of the board...  Assuming I ever get the damn thing back!  I'm 80% sure that I inspected the back of the board and there was not any solder joints or PCB leads sticking out abnormally.  According to their RMA site they sent it back out 3/23 but there isn't a tracking number...  Throughout this whole process I have sent them 5 emails and they have responded to precisely 0 of them.  The only way I have gotten a response is by calling or by social media...  And social media was just them mocking me.  If I don't get the board back in the next day or so I will be calling again.
 
I did end up getting a great deal on an ASUS Sabertooth Z97 MKII for $100 with remaining warranty until 9/2019 (not that I ever hope to use it).  I did have to email ASUS support to get verification of the remaining warranty based on S/N and they did respond within a day which is at least somewhat promising.  Still haven't had time to put it all back together and see if it catches fire again... maybe by this weekend.  :)

WackyWRZ
I haven't forgot my promise to post up pictures of the back of the board...  Assuming I ever get the damn thing back!  I'm 80% sure that I inspected the back of the board and there was not any solder joints or PCB leads sticking out abnormally.  According to their RMA site they sent it back out 3/23 but there isn't a tracking number...  Throughout this whole process I have sent them 5 emails and they have responded to precisely 0 of them.  The only way I have gotten a response is by calling or by social media...  And social media was just them mocking me.  If I don't get the board back in the next day or so I will be calling again.
 
I did end up getting a great deal on an ASUS Sabertooth Z97 MKII for $100 with remaining warranty until 9/2019 (not that I ever hope to use it).  I did have to email ASUS support to get verification of the remaining warranty based on S/N and they did respond within a day which is at least somewhat promising.  Still haven't had time to put it all back together and see if it catches fire again... maybe by this weekend.  :)

No use the social media to get what you want, nothing is worse for a company than bad PR.

FINALLY got the board back from them.  They put a nice hand written note in there letting me know that this board is "not repairable due to customer damage - pcb burnout"  .  Anyway - as promised here are some pics of the back of the board.  Upon closer inspection the plastic PCIe bracket pieces stick out MUCH farther than a solder blob or component leg would so I am quite sure nothing grounded out on the case.  It looks like traces lifted on both sides of the board - and the PCIe slot solder pins are actually missing it looks like - so I am going with some sort of short in the PCB layers.  Also on that copper piece where the major discoloration is - that is where that Capacitor is - so I am pretty sure that was the root cause.
 
Click for Hi-Res pics:
 

 
 

PCIe socket, meltdown & GPU damage would make me guess the issue was in the socket (top side) and the bottom of the MB was just collateral damage.
 
 
Just my 2 cents.
 
Hope the new Asus MB works out for you.
 
GL

I'll almost always use Gigabyte Boards or EVGA boards. Your motherboard from asus can come from the factory shattered in a million pieces, and they'll literally scoff at you. Gigabyte has been nothing short of outstanding for me. I'd rather get shot by a Hi Point than own an asus product.

WackyWRZ

BF3PRO
I'll almost always use Gigabyte Boards or EVGA boards. Your motherboard from asus can come from the factory shattered in a million pieces, and they'll literally scoff at you. Gigabyte has been nothing short of outstanding for me. I'd rather get shot by a Hi Point than own an asus product.

To each their own...  Your GB board could start on fire and they'll literally scoff at you too.   Trust me if I could have found a good price on a EVGA Z97 I would have been all over it.  There's one in FS/T now but too little too late!
 

Is this a widespread issue?

Here is my opinion:
The source of the heat had to be inside the motherboard or at the surface of the motherboard.