Okay, feeds have been broken for most of the last 48 hours for most people. The reason that they were broken is that Blogger used to put the feeds in my root folder, but now they're placed in my blog folder. In addition, Blogger in Beta no longer creates an RSS feed by default...only Atom.
So the issue I had was two-fold. First, since I'm on a managed hosting solution, how to I redirect people from [root]/atom.xml to [root]/blog/atom.xml? Second, how to I get an RSS feed for people who can't use Atom?
What I ended up doing for the short-term was deleting atom.xml and rss.xml from the root of my site and creating subdirectories there. Those subdirectories are actually ASP.NET applications whose default pages redirect people to the blog using Response.Redirect.
Now when you ask for /atom.xml, the site redirects you to /atom.xml/Default.aspx, which then redirects you to /blog/atom.xml. It's inefficient, but it takes advantage of the HTTP standard to get the job done.
Now I need to get back to work on finishing the Atom/RSS conversion helper, and find out why Blogger thinks I'm a spam blog...