Robert has pointed out the very-cool looking Snarf!, which adds an aggregator to the search bar. Definitely going to play with this more. Even better, I might actually be able to use it at work, as it doesn't require installation of anything (it's just an ASPX in the _search frame).
What I was thinking of originally was more along the lines that of the server control that Chris is using, something I'm also going to check out if he lets me.
Ultimately, what I want is something like DotNetWeblogs.com, but spanning all of my RSS feeds. The only thing is, I know that building anything at this point is really just a pipe dream. I have so many pet projects I want to do and never have the time to do any of them.
Some day, some day :)