Hey, I don't know if yall know about this or not, but I found this website today and you can download 3d files in almost any format of any drive you can think of. I imagine this will help quite alot with design stuff.
I was playing around with similiar sites last night! I downloaded a stepper motor from somewhere... another part from somewhere else... and started building my virtual router.
There is a whole collection of sites that have the 3d parts net included in their catalog, and on the main site there is a group that can be joined where everyone contributes drawings. the main contributors are those businesses that are selling parts.
Maybe also look at these sites for downloadable cad files:
It's getting more and more common for manufacturers to have cad files of their products on their home pages, so if you have a part which you need a drawing for than check the relavent home page.