You might want to shop around at places like 3d cafe. They have a lot of models already built and free for use.
http://www.3dcafe.com/only problem you might run into is converting them to bin format. But look around, there are converter programs that'll help you out.
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For crushed cars, you might check the mtm1 models here at mtmg, and for cranes there is one in the mtm1 section as well, and there's crankshafts nifty bit of heavy equipment in the summer contest 99 section.
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- Phineus