the failure happened after a year of use - Apple Italy refused to make the repair under warranty "as it's not a known issue" and "your business bought them so you only get 1 year warranty" - I did get the impression that if my MBPs were private then they would have helped.
The repair cost about 500 euro each (431 +VAT), and involved replacing the entire motherboard. Apple had to order specifically the motherboards, so they will be aware as a company - how many MBP mobos are being re-ordered and whether this is statistically more significant than other previous MBP lines.
My understanding of the fault is that in the 2011 MBP the Quad-core intel i7 and the discrete AMD Radeon HD 6750M/1GB GPU share a small heatsink, which can over time damage the GPU. Is it due to the focus of the heat issues on a single heat disposal element?
Note that from my experience - around 75% of 2011 MBP will fail!
full details of a couple of my failed MBP's here :
#1 MACBOOK PRO (15-INCH, EARLY 2011) Serial: C02FX50xxx CPU: Quad Core i7 2.2GHz HDD 750GB 8GB RAM
Diagnosi Problema: video intermittente GPU stressato
Questo MBP Serial C02FX50xxx e stato analizzato da Apple e richiede un nuovo Logic Board 2.2GHz 661-5852
#2 MACBOOK PRO (15-INCH, EARLY 2011) Serial C02GC2xxx CPU: Quad Core i7 2.2GHz HDD 500GB 8GB RAM
Diagnosi Problema 1: CPU stressato, ventilatore a 200% quando CPU supera 10% di attività
Diagnosi Problema 2: Batteria dura poco
I have to say that since the repair my primary MBP has worked fine, but then I treat it much more carefully and don't hardly use the discrete video card,
#2 Above "was repaired" but still has 200% fan when the CPU activity goes above 10%, one of the other failed MBPs is working with a new mobo and the 4th is still struggling with occasional intermittent video.
for home use, instead of an MBP, I bought cool-running Core-i3 Mac mini - as I can't see that mini having heat issues when just outside of warranty! I bought my daughter an enterprise class Lenovo Core-i3 for her college instead of a MacBook Pro. It hasn't melted yet!
I lost some trust in Apple over this design quality error and and over the mis-direction of the company concerning the denial of the fault. Four out of six is not a single data point - it's a whole quality graph of failure.