Leica D-Lux4
Seriously. Or save money and get the Panasonic LX-3. Another choice would be Ricoh GX-200 or GRD-2 (if you can live with fixed 28mm). I just bought (and now sold) a Km/K2000. It is a *great* body with excellent IQ, improved AF, and with my 43ltd lens up front is was much smaller/lighter than my K20d. But in my hands (which are rather large), it actually wasn't very comfortable to use as it was just too small. Same issue with the G1. I have decided that if I'm want something smaller than my K20d with a ltd prime, it is my DLux4. The middle ground of a tiny dSLR just doesn't work for me. Too big to fit in a pocket, too small to fit well in my hand for long-term carry. But ymmv.