Originally posted by Mountain Vision This is true. A K-mount camera can definitely be made lighter and smaller, perhaps by losing the mirror/AF system. This we know because the MX, Program Plus, P30T and so on were tiny compared to most of the Pentax DSLRs. So Pentax can definitely make a smaller camera if they want to.
Looking at the film cameras is a false start, I'm afraid.
That's because a digital camera - be it DSLR or MILC - has much behind the sensor (which is itself quite thick compared to film): the SR platform, mainboard, a LCD which should be articulated. Then there are 2-3 electric motors - AF, mirror/shutter, aperture. And a large battery.
You should take a look at the KP instead. They might be able to reduce the size just a tiny bit.