After much messing around with what appeared to be 4 faulty routers in a row I realized that I can reproduce causing my DLINK DIR-655 router to freeze up and require a hard reboot (to factory setttings) by simply plugging in my Lenovo W520's ethernet card.
I was also able to reproduce this on my old Asus RT-N16. I went through 4 routers (3 Asus and 1 DLink) and can reproduce this.
Does this sound like a possible?
Yes, it's very possible. Loopbacks (typically caused by bad cabling, an actual network loop or a faulty NIC) can create a broadcast/multicast storm, which can put pretty much any network device to a halt.
We've had $1k routers going down because of this, so it's not only consumer grade stuff that freezes.