I don't see why a k-mount mirror-less camera is that unlikely, even if the k-mount necessitates that it would be roughly the same dimensions as a camera with a viewfinder.
While it wouldn't be much smaller, it would be
easier and cheaper to make, as it wouldn't require a mirror or a prism/mirror or a viewfinder. All these bits are expensive and require precise alignment adding to cost and manufacturing time.
While I'd still prefer a viewfinder, most people I hand my camera to try to take photos at arms length before I tell them "to look through the little window like on your Granddad's camera." I got asked today if my camera was really cheap because of that! The impudence!