Boykin pointed me to an example of where he'd used the ad-space method, but he didn't want me to publish the URL. The most interesting thing I discovered about his page choice was he'd done his homework. It has 125 .edu domains and two .gov domains among those linking back to it.
I've long said Google very much approves of links from .edu and .gov sites due to their "authority." Boykin's heard me say it many times before.
As he himself says: "To me, that was the selling point. Personally, I could care less about PageRank."