I am a heavy user of Amazon Web Services. I usually need to stop/start instances as I am developing or hacking at something, and often I need to get the IP address of a server so I can ssh into.
So I started a little project that uses python and boto. It is not tested. I don't think you need anything other than the default python.
If you're interested, give it a try and let me know if it works.
Set the region you want to search:
ec2 config region=us-west-2
Search for EC2 instances. It will search all properties of the EC2 instance. You can use a single keyword, or multiple keywords to refine the search. The pubic IP address will go into your clipboard.
ec2 find killroy running