One can drive latency almost arbitrarily low if one is willing to give up exact knowledge of a where the data is.
A simple example is N out of M writes (N and M can be arbitrary with N <= M). M is a set of machines, N is number of replicas we want to have. Now at any given time we write to the N machines that respond fastest. Data is now arbitrarily sprayed over the M machines, but as long as the data itself has ordering information the right state can be reassembled by talking to the M machines.
The "spray" can now be controlled by favouring some nodes from M up to a timeout (i.e. we put more uncertainty in time). We can reduce the reassembly work by using learners and hence increase the likelihood that one machine has all state.