Comment Spam Control

If possible i think a plugin to control global (or per blog basis) comment spam.

I currently use a wp plugin called bannage > http://www.justinshattuck.com/bannage/
It does seem to work as you can ban commentor by ip, url, name and email, however every now and then the blacklist seems to get deleted, plus it only works on a per blog bases (needs to be manually activated and the banned people need to be re-added for each blog)

Something like that that worked for the entire site and not just per blog would be perfect.
Say like i enter the admin panel, enter for example the ip i want to ban (like 127.0.0.1 or 127.0.0.* *being a wildcard) and it then banns them from the site (or at least bans them from commenting),

what you think? is it possible?