It would be nice if Arduino could post the mechanical specs on the board, especially the mounting holes & connectors. I'm attempting to mount the board in a 'box' and it would save all of us doing similar work a lot of time rather than measuring all the dimensions.
Not sure whether they do, but I think I noticed a slight change in the mounting holes between the Uno through-hole and SMD versions 
There are several third-party drawings around including my own (www.robgray.com/temp/Arduino-PCB-dimensions.pdf) I haven't seen official ones though which make me wonder why that would be the case, surely that's part of normal documentation.
Rob
One option is too look at the outline on the Eagle files. It has the layout.
True, but not everyone uses Eagle. Why can't some proper engineering drawings be made available?
Rob