p.s. this is an old thread, but I've been relatively happy using a Panasonic LX-3. It can have a little CA on high contrast edges, but given it's WA and nice functions, it fits the bill and is quite affordable.
As both a climber and a photographer I use both a 30D (with 70-200 f/4 IS) and a 5D (with either a 17-40 or a 24-105). No weight problem since I only boulder (Fontainebleau). I often use off-camera flash and a reflector. Photos on Bleau à bloc.
Leica D-Lux4 or Panasonic equivalent? The optional viewfinder means you don't need to hold it at arm's length to see the LCD. Image quality is more than excellent. Very robust too.