I updated my (n)echo feed to the Atom 0.2 snapshot as detailed by Mark. I am using what Mark calls a maximal feed with feed author. I made a few small changes to Mark's templates (#entries for example, and I am not publishing the Extended Entry data in the feed) and it still validates. The feed can be found here and is still named necho.xml, as not to break to those aggregators that are already grabbing it.
And a button to go with the feed: