A tough call. All the cameras mentioned thus far have been good ideas.
The Nikon 1 series is a CX sensor size which is the same as the Sony RX100 the other ones listed on the page tizeye referenced ( http://www.dpreview.com/articles/236...ompact-cameras
) are a bit smaller but not by much. All of them seem to follow the fast lens plus larger than P&S sensor size to achieve high IQ and low light performance. Among those cameras I will point out that the Olympus XZ-2 can be outfitted with the Olympus VF-2 electronic viewfinder more commonly used with the Olympus Pen series of cameras.
I would agree with what others have said about the FZ200, it is an all around excellent camera from everything I have seen and if you were going to shoot wildlife (there is some around there fwiw) then I would say the FZ200 is the one camera that does it all.
Since you didn't say that and did say small size and 100mm equivalent reach it makes more sense to look at those enthusiast zooms in the dpreview link.
I personally favor micro four thirds and would recommend you at least peruse the Olympus offerings. The OMD is a great camera and has a built in EVF but you can also get the same sensor in the E-PL5 and E-PM2 for alot less money. The new 16MP sensor in these cameras is made by Sony and offers great high ISO performance, providing several f-stops of use ability beyond what you would get with the enthusiast zooms or the Nikon 1 series. While you might not be able to get away with a single lens you could use a compact zoom like the new Panasonic Lumix 14-42mm x zoom (28-84mm equiv) and then grab the Panasonic 20mm f1.7 pancake lens for low light, maybe an Olympus 45mm f1.8 for something longer and low light. These lenses are all very small and can easily be stowed in a pocket, which would give you the flexibility of carrying it all in your pockets while still maintaining better performance.