In reply to Flinticus:
Agree with Kenr on the finger rolls. There was a recent video by I think the German team regarding a secret exercise which turned out to be dumbell finger rolls.
Another great climbing exercise would be renegade rows. Get in the plank position with hands on the dumbells on the floor. Then row with one arm then the other. Increase the weight to an appropriate level. Might work better with fixed plates or those dumbells with flat sides.
If the plates are round and spin freely you could also use them for ab wheel roll out type of exercises and also incorporate fly type exercises that are normally done with rings.
Kettlebell swings can also be done perfectly fine with dumbells, a posterior chain exercise working the same muscle group as deadlifts.
Eric Horst recommends the dumbell snatch as a good core exercise. Explained here at about 7.5 mins in:
http://nicros.com/training/videos/video-core-training-for-climbers/
There are also straight forward one arm dumbell rows for a basic pulling exercise.