This is something I’d like to do:
Blogger Buzz: AJAX Search API Hackery
... the sidebar's "Google Search" field searches multiple indexes (Web and BlogSearch), as well as individual site-restricts (in this case the AJAX Search API blog, the Google blog and www.blogger.com) - you can customize any of these ...
If I get it into my blogs I’ll update this post with details.Update 9/26: I haven't had time to play with this, but see the comment from Marc Lucovsky about dong this. Marc has a topic-specific blog on AJAX search as well as a quite interesting personal blog. I've added both to my Bloglines list. BTW, I'm a fan of topic-specific blogs, which often have well defined lifespans. Ideally when they reach retirement they should be replaced by a summative web page, but that life-cycle completion is probably overkill for many resources. As I was told by a former boss (repeatedly, evidently I didn't get it the first time), don't let the perfect defeat the sufficient.