Let's just wait for Teamspeak V3 to be finished, it'll have enough features so I can create what you need for kinda emulating this feature inside of blockland.
eg: starting teamspeak server together with the blockland server, also starting a lighttpd server that is used for the users.
creating a ingame guy that communicates with the blockland server, and the blockland server communicates with the lighttpd server and the lighttpd server communicates with the teamspeak server, making it possible to use commands like /muteplayer username etc.
may sound complex, but it's just a simple step to make this possible,
only thing that bl players have to do is to connect to the corresponding Teamspeak server, but I'm sure using magnet links will solve this.