Optimizing Paxos with batching and pipelining (2012) [pdf]

For some other, newer approaches to improving paxos performance, especially in high or variable latency environments, folks may be interested in epaxos (http://delivery.acm.org/10.1145/2520000/2517350/p358-moraru....) and wpaxos (https://arxiv.org/pdf/1703.08905.pdf).