A tool to automatically generate a historical report from bugzilla

I need a tool that can generate a particular report out of a bugzilla database. I want to generate a "burn-down" chart automatically, showing daily bug counts for a given query over a specified time period. This must be generated in arrears, i.e. the tool needs to scan bug histories and figure out what state bugs were in on each day to determine if they match the query. Preferably, this tool would access the database via the Bugzilla xml-rpc interface, or by scraping the web interface. In other words, it must run external to the server and not require special access. I'm thinking this is pretty simple for someone who knows bugzilla. If not, tell me how complex the project would be.