You might want to check out the new Panasonic DMC-LX2. It was just announced today so i haven't checked out all of the specs. From a quick glance it seems to be what you are looking for minus the optical viewfinder.
2.8 in LCD
400 ISO (3200 max)
187g (heavier than you were looking for but not much)
4.16 in x 2.2 in x 1.04 in