Ryan Barnett was kind enough to point me toward this announcement Distributed Open Proxy Honeypot Project Data Released. It states in part:
The Web Application Security Consortium (WASC) is pleased to announce the inital release of data collected by the Distributed Open Proxy Honeypot Project. This first release of information is for data gathered from January - April, 2007. During this timeframe, we had 7 internationally placed honeypot sensors deployed and sending their data back to our central logging host.
I recommend reading the report (it's a slide presentation) to get a sense of what these Web honeypots are seeing.