Couple things you could try.
create serveral shoutcast folders with names like, shoutcast1, and config the red5-web.properties in each WEB-INF folder.
THe other one is to extend the application with java, and set attributes to subscribers. Then add a method to get count that requires a string. get the string from post vars, and then enumerate the clients that have that attribute.
You see, stats servlet was only to show you how to access the application from a http request. Just an example.
Currently I am working on an nsv encoder. There has been some work done on the shoutcast app. Looking at loggin bandwidth to SQL tables, and other play stats. THere is no E.T.A. You know though... If I put too much work into it I may create separate usage licenses. Such as free for personal use, and small license fee for commercial providers. Shoutcast is self funded and a hobby. I have other priorities such as freelancing my room and board.
But yeah. some more dev has gone down in the encoder department.