So from my little bit of research growl supports sending notifications across the network? And you'd want a refresh based on one of these?

Besides that I don't run MacOS X on any computer (nor do I want to) so I can't even test it, it feels a bit hacky and special purpose.

A refresh can be forced through the command prompt. Something I should do is create a script that will send the appropriate message to the command prompt on behalf of the user. This could then hopefully be connected to other types of events or a button or whatever.

EDIT: if this sounds like what you want, file an enhancement request or I'll never remember to do it.