I have just finished a draft of my Ruby web server review, I have uploaded it to my scribd account, This is still a work in progress and I am looking at improving it further and may be include Unicorn tests as well.
Here is the document:
While at the topic of Ruby web servers, I highly recommend this article by Ryan Tomayko on Unicorn's architecture.
Edit: I didn't know that scribd requires you to login before you can download the files, here is a direct link
