Research for a university project. - Bike locks

I agree with you completely about the links, that's why I decided it wasn't a go-er.

The main aim of the project judging by the survey responses so far, is to provide at least the same amount of protection as the strongest D locks, but be lighter and easier to carry, hence trying to incorporate it into a bike part

Compromise. Strongest will mean heaviest. Lightest will mean weakest. It's why vault doors aren't made of particularly light metals.
Without sounding like I'm shutting you down, You'll need to think outside of the locks protective limitations. As in not how the lock will preform WHEN it's being assaulted, but rather how the lock defends itself. Outside of Hardened steel, you'll start getting into the funky stuff to produce the lock or save weight: Hardness scale

Your most common target is this: Fahgettaboudit In terms of compactness, safety and durability, it's the most popular (Unless someone cares to debate that) But it's a heavy bastard. Can you make it lighter? If not, can you make it less cumbersome?