Id like to interrupt and say that i feel Lewis' chin may worry people more than is actually demanded. When Lewis did get stopped, it was as a result of MONSTER shots by Rahman and McCall. In Rahmans case the punch was the definition of a one hit wonder and legitimate excuses can be made.
The only reason that his lossses by stoppages are concentrated on is because Lewis didn lose on points...EVER. To beat Lewis you had to nail him to the Floor and even in the Titanic Heavyweight division only 2 could do that. (One by accident.)
So i do feel that Lennox's chin is less an issue than some might think.