Have you exhausted all possible ways of getting traffic to your blog? That would be my first avenue. I agree with Walrus, the pages can add up pretty fast. I have so much unfinished crap so I've never thought of doing anything else with the blogs I have on the root. But I've just kept posting away, well not always me making the posts, but anyways, I've found they continue to grow with traffic. That is, the ones that are interesting.
I would rather see them grow with SE traffic or reader traffic. I guess I see my blogs as something that grows over time. Sure much better than a submit and forget free site that will die out pretty quick. I personally would rather make more posts on my blogs, or make more blogs, than spend that time making sites, but thats just my opinion...
ronnie