Good way of monitoring vhost traffic

I'd like to monitor and limit traffic to Apache 2 vhosts, eventually shutting them off if they breach a predefined amount (settable per vhost, if possible).

mod_curb does this for a whole server for Apache 1.x but hasn't been ported to Apache 2 yet. The author says he isn't immediately interested in doing so, but the code is available.

Are there any other ways of doing it? Currently I monitor using awstats and a custom BerkeleyDB that bytes are logged to for each vhost, hooked into the apache2splitlogfile script that does vhost logging.

Thanks for any ideas.