Praetorian Helmet: what does it look like?

[richsc]

Caroline Lawrence, the author of the Roman Mysteries, is starting work on a new series, Roman Quests. She wants to put a praetorian helmet on the cover, and is looking to RAT to help get as accurate a depiction as possible. The first mockup had a kind of centurion helmet with a nose piece, so I know we can do better than that.

Kevin Mills suggested pinging Graham Sumner. Other opinions?