I have been making a dough in accordance with Dave's NY style dough recipe. At the moment, the dough is about 65 hours old. My plan is to go for at least 4 days. I know that Dave has indicated even longer times are possible and I also recall that varasano has reported in the past using doughs that are even older (although he says that 3-4 days is more typical). So, there is some precedent for long fermentation times under refrigeration.
The photo below shows the Canadave dough after 65 hours. The bubbles in the photo usually indicate either too much yeast or overfermentation. If I had to guess between the two, I would point a finger at the yeast. I typically use 0.25% or less (IDY), by weight of flour, for my typical Lehmann NY style doughs. By my calculation, Dave's recipe calls for about 0.76% IDY. In making Dave's dough, I also used fairly cold water and achieved a finished dough temperature of under 70 degrees F, which is quite a bit below the 80 degrees F finished dough temperature I usually shoot for. My refrigerator compartment has also been on the cool side, and was a bit over 39 degrees F this morning. So, these numbers don't suggest overfermentation. I won't know for sure, of course, until I am ready to use the dough. If it's the yeast, then it's possible that I will still achieve good results because any excess yeast will simply die off once the dough reaches 140 degress F in the oven.