I DID see someone dress as Polgara once at a con in Ohio. I asked her if that was her costume, and she told me it was.
I want to see Redwall fursuits, personally.
On the topic of Discworld, I've done Maladict from Monstrous Regiment, and people knew who I was even at a small con.
The Rincewind is famous now! One of my friends saw him too and told me.