Hi Mark, thanks for working on this.
THe "Immediately lock out invalid usernames" is great. The only problem is that if someone makes a typo they can get accidentally locked out. When I turned this on, it was only a few hours before someone did this.
It would definitely be great to just be able to specify that "admin" always gets blocked, or that "XYZ always gets blocked".... or at the very least, if you try it multiple times you get blocked or something.... with some kind of warning about it.