I don’t know how were created Shardblades and Honorblades, so I do you know about exact number of Honorblades either. They are powerful and precious, but opposite to Shardblade, Honorblade vanished after the death of the owner. This way they are unique, but maybe they could be created not only for the Heralds? Unless of course it was a special gift from the Almighty.
Other surprise (for me anyway) is: Talanel’Elin - 10th Herald kept Shardblade when died on the end of book – what happens with his Honorblade?