Hey all,
Having just finished a fairly detailed model, I went scouring the web for sources. I located one non-standard one, which some of you might find very helpful (and a pointer for future projects).
In trying to get the Merlin engine right, I eventually located a 3D model of one.
http://sketchup.google.com/3dwarehouse/details?mid=8954fd105dd242c398b8c800ae001b66&prevstart=0
This is for a program called Trimble Sketchup (once upon a time Google Sketchup), which is free! You don't need to learn much about the problem to view the model, zoom around it, and zoom in and out. From there, you can measure parts of it, and angles too. Many of these 3D models are contributed freely by users worldwide. There are a few relatively useful resources, but you never know what someone might add.
Maybe in this thread, you could add similar unusual finds, as a resource for everyone.