Well, lets summarize: we need advertising to "reach out to the power user and sysadmin communities".
What about a "referrals" system? I reference some people, and if they register because of my reference, I earn X reputation points (and possible badges) - and so on the person that registered. There are a lot of wesites that do this kind of thing. I thought about it after I used Dropbox and remembered they have this approach.
This way you don't have to "pay" for advertising, you're using the users that think referring someone it's worth. Of course there would be a lot of statistic rules need to avoid people gaming the system, but I don't think it would "harm" the system at all.
You don't pay these people with advertising money, you pay with visibility in the community itself with reputation points.
What do you think of this idea? Would this "cannibalize" the reputation system? And, most importantly: would it be effective?