I was talking to brandonW about this. It could be anywhere between 2-4, but I feel like he bricked 3, (he bricked all that he had at the time).
He was trying to install the 05 key in the certificate to allow third party OS's to be installed by being signed with the 05 key. Free83p, was the end result of this.
I think he bricked all of them within a week.
But it should be known that he recovered all of them using a boot code hack. So as of like November, he hasn't permanently bricked any.