Ahem, I sweated over whether this was being too overly promotional or not, and then I figured that a great deal of us are probably trying to create sustainable business models with our WPMU sites and thus, reading about the entire Edublogs.org story might be of interest:
http://wpmu.org/making-money-with-wordpress-mu-the-edublogs-story-so-far/
With luck this'll help some people not make the (many and varied) mistakes we've made along the way.
And also I'm wondering if people have any other ideas!
No need to leave a comment there btw, feel free to lemme know what you think here :)
Cheers, James