I agree, first pre-tension cables then replica bridge contests.
I think it would be really cool if a few levels were based on actualy locations, like say the Brooklyn Bridge. Either that or have pre-made levels that were models of real bridges for people to study.
Very cool idea. Maybe it's even the basis for a contest. "Who can make the most accurate model of the Golden Gate Bridge?" CL would supply the landscape for the level and would judge the bridges on scale, strength, and fidelity to the original. One slight problem with this is that the current state of the editor and materials are not quite up to the task of accurately modeling a real bridge. See the discussion of pretensioning cables in this forum for one reason.
I agree, unless CL is up to the task of adding pre-tensioned cables to the game, many bridges would be out of the question to try to re-create. There are many others that would still be possible on the other hand. I think this deserves some looking into!