The "recipes" page has some good examples: http://bit.ly/938bnt dynamic configuration, leader election, distributed queues, distributed locks, group membership, etc...
Sounds like an interesting challenge, if you're up to it please start a discussion on the dev mailing list http://bit.ly/cpVqnb It would be interesting to see the results. Java is currently used because that's an environment that ops feels pretty comfortable with, erlang would be a great option esp if it's faster, more reliable, etc... I've heard some interest in .NET for the server as well.
In reality this tends to not be a very big issue. Typically for online production serving you want 5 ZK servers (in case you take one out for maintenance you could still suffer a failure and the quorum would be maintained). Once you setup the ensemble (cluster) it typically doesn't change much. There are some cases where this is useful, but they are pretty rare. Furthermore, you usually don't want just any process attaching to the ensemble, specifying the host/port explicitly is a security feature of sorts (granted not perfect though).