Our super nice readers OG, Ben and Richard sent me some very useful size comparison images. On top you see the comparison with other FF cameras like the Leica M9 ($6500 camera!) and the Canon 5DmarkII ($3400). The RX1 is incredibly small and has the same size of the already tiny Panasonic GX1 (here on Amazon) that uses a much smaller Micro Four Thirds sensor (Click on the image below):
And if you compare it with a Nikon D700 with 35mm f/2.0 lens than you get this (again click on pic!):
From an engineering point of view this is an amazing piece of technology. I hope Sony is reading the SonyAlphaRumors readers comments and make an interchangeable lens version of the RX1. Our readers already have their hands on the credit card for this :)