Quote Originally Posted by dolina View Post
I completely forgot that Nikon had mirrorless offerings.

It appears that Pentax has withdrawn that product from the US market.

As for the Sigma it doesn't fulfill smallest or lightest parameter.
Fair enough as this is your thread. But the DP Quattro's aren't really all that bulky but rather oddly shaped to make storage/transport somewhat awkward compared to the brick shapes of the DP Merrill's as well as the other cameras listed.
But the Leica X-U is also not particularly small, for an APS-C compact relatively speaking, but has the advantage of being water and shockproof.

I guess what I'm getting at is it becomes extremely difficult to compare the relative performance of each ''compact'', especially if we look at sensor size alone. As these are not ILC's, the lens cannot be separated from the equation.
They vary in performance and speed and a faster lens with a smaller sensor may perform better than slower lenses with larger sensors, shooting conditions dependent.

I get what you're trying to achieve but its a very difficult task as small and compact is a relative term, whilst there are too many variables to consider when considering fixed lens cameras to just base it on sensor size alone.