Well, as for me was a hard work to find the physical dimensions of the Arduino Mega 2560, once I did it, I decided to post it on Thingiverse, if someone else can help.I think with the Eagle software can easily be seen but I'm more mechanical than electronic so I put it in DXF file.The dxf file includes images of RAMPs board and Arduino, probably you will have to reload them. I put them in Images.rar file.