In reply to Toerag:
I believe the Canon 100D is the smallest APS-c dSLR.
However, the mirrorless system cameras are smaller and lighter with good picture quality, the sony NEX line and Micro four thirds systems are all good. Mirrorless is the way forward.
A 'bridge' compact would probably do the job fine. The Sony RX100 ii (or RX10 if you want more zoom), have great sensors and are well regarded.