I have a Sony RX-100 v1. It's is very compact, and quite good. Shoots RAW. Has some cool features (panorama mode, very good video mode etc). Plus it has the same dxomark score (66) as the Canon 7D
If you can get a v1 RX100 like mine, I've seen them available quite cheap new, now that the v2 and v3 RX100's are released.
I would also find the Ricoh GR tempting. Prices seem to be coming down.
Or a recent Sony NEX - eg the NEX 5000, NEX 5 series, NEX 3 series. The kit 16-50 is very compact, and of course there are abundant cheap NEX>PK adapters for Pentax lenses. NEX's are fun cameras and some - eg the 16MP NEX's - have sensor performance that will be very familiar to K-5 users.