When I was reading the book I was a bit confused and thought Dawnshards and Honorblades might be two different names for the same thing, but I know better now. (Person in front of me at the book signing had a question relating to them.)
What was the question and answer?
Unfortunately, I don't remember his exact question and answer. But that group ahead of me in line was pretty interesting in general. They talked about Cryptonomicon (by Neal Stephenson, not fantasy, but still fiction) a bit, and a female in the group had the first normal copy (not an advance copy) of the
5th 4th Librarian's book that Brandon had ever seen.
Actually the person asking the Honorblade/Dawnshard/Shardblade question had the names for the swords a bit mixed up, part of the reason I interjected with a correction and a follow up question, which I think was a bit rude on my part. I believe my follow up question/statement was along the lines of "Oh, I had thought that Dawnshards and Honorblades were the same thing, that makes me wonder what's up with Szeth's shardblade." Brandon's response was along the lines of a knowing "Hmmmm..." or "I wonder...", which could have just been a cryptic way of misleading me, and Szeth's shardblade might in fact be perfectly ordinary, and we just haven't been exposed to enough shardblades to make this obvious.
What makes you think a dawnshard is a blade? Shardplate also has shard in the name. Shard seems a material/origin description....
Looking at the few places in the book where Dawnshards are mentioned, there's no great reason for me to think that it's a weapon. It's just one of those ideas I latched on with my initial incorrect assumption that it was the same as a Honorblade. The reason I thought that was because the Honorblades seemed to be proof and part of the Heralds' binding to their individual cycles of reincarnation and suffering.