Human-Made Viruses of the Real World
Self-Replicating Machinery is a very interesting topic, one of which definitely needs more research. While we're still a ways out from seeing tangible results, it's a cool theoretical topic that can be fun to brainstorm about.
What first inspired me to look into this topic was a paper written on a Virus Writing forum I was browsing. Obviously in love with self-replication, virus writers seem to have a keen interest in the concepts of self-replicating machinery.
I don't have many notes on my own at the moment, but you can check out these links for a few interesting documents and websites that discuss the topic.