The data replication is a separate issue, you're going to have to have some form of replication whatever technique you use for the actual balancing.
I think it can provide load balancing within each cluster, for some applications, eg. mod_backhand.
Usage of multiple IPs is going to happen one way or the other (real or RFC1918) which ever solution you use.
How is it not redundant when it ensures that a particular IP is always providing service?
I think it's a pretty cool solution for some applications, have say one cluster in the UK, one in the US, with DNS pointing to both clusters. Anyway, it all depends on exactly what you're trying to achieve, "load balancing" is a very wide ranging function..