Per our conversation. Specific action items:

1) autofill _id's in rs.intitiate()
2) autofill _id in rs.add()
3) support array of hostnames:

rs.initiate(['host1', 'host2', \{host:'host3', arbiterOnly:true}])

I think it is possible to do this all in the JS helpers, but it might be better to do it server-side so it works from scripts written in other languages.