[obican]

There will never be a truly small FF DSLR as long as there's a LCD behind the body.




Have a look at this picture. Have a look at the flash shoe and the viewfinder hump. Just to the left of it, you'll see the film plane mark. Notice how close it is to the back of the body. That's because film is very thin and there's only a pressure plate and a thin metal cover behind it.

Now have a look at a Sony A7:



Keep in mind, this is the Mark I version. Mark II and III series bodies are much larger and fatter. Do you notice how far the sensor plane is from the back of the camera? That's because there is so much junk behind it. Add the mirror mechanism in front and you'll realize a 35mm FF DSLR will always end up being a fat thing, compared to film cameras.

Even the hilariously obese attempt of a retro camera called Nikon DF is useful in such a comparison:



Unless you trim the mirror in front or the LCD in the back, there'll never be a small digital camera with a 35mm FF sensor and an interchangable lens system.