I just saw this over on kickstarter.com. Not sure, but as I recall Titanium is very difficult to cut through. This guy is creating a bike lock made out of titanium. Figured I'd post it here in case anyone is interested. (If I'm wrong about the strength of Titanium, please disregard)

The usual disclaimer: I have no relationship to the project being funded, don't know the guy, etc. Locking bikes comes up a lot here, so I figured I'd pass it along FWIW.

http://www.kickstarter.com/projects/...-bike?ref=card