davem, thanks for the link
I believe Megan of Houghton Mifflin stated the number of copies was in the hundreds, but not thousands. I would assume these were split between HM and HC, which would have me guess at a max of 500 total, 250 for HM (if they were split evenly), but I don't know if HM would give them all to B&N.
I think the limit of 5 per person was simply a B&N standard and was not considered for the specific event or based on how many were available, and then when all those phone calls started pouring in they began to realize what the demand would be like
I definitely think there is going to be more than 10 or 20, but I can't imagine more than 200/250. Which means if you're past number 100 in line, you won't have much luck.
The fact that there haven't been any other announced events makes me think the number is so small, that they didn't bother giving some away in LA or some place as well, so it could very well be they have more like 100 to give away.
However, our copies are from HarperCollins, not Houghton Mifflin, so this leads me to believe that HC still has their share, why they haven't announced anything is beyond me, as I haven't heard of any other events either.
I'm in the same boat as you regarding feeling a bit upset about this whole situation. I've had people from NY tell me they will be going to B&N, and they saw the films but haven't read the books yet...so obviously these copies are probably not going to be distributed to the biggest fans. And selling for loads on eBay is simply going to disperse them to the rich.
I think the other 2 copies we give away will be based on a trivia contest, or at least one will be, that way at least those who know a lot about the stories will have a higher chance of winning.
Best of luck in getting one