For my Mechanical modeling workshop I did at the Blender Conference I made a steam engine. After Bconf i added some details to the model, animated it and used the tips that andy and matt gave at their workshop for the lighting and compositing.
i also made an animation: http://www.members.lycos.nl/blenderonline/steam_engine2.avi (XviD)
The workshop that i did can be seen here: http://video.google.com/videoplay?docid=8813418839614672244&hl=en
the .blend file that i used for the animation: http://www.members.lycos.nl/blenderonline/mechanicalmodelingworkshop.blend
there is also a document that i made with all the steps in it, but i need to update that with the animating part. Ill upload that later.