Rackspace Cloud Files supports this. The file "test_javascript.js" was saved non-compressed. It works the other way, too (compressed->uncompressed if the client doesn't support compression):

    $ curl -i http://d.not.mn/test_javascript.js
    $ curl -i -H "Accept-Encoding: gzip" http://d.not.mn/test_javascript.js

This isn't trying to take away from their announcement. I'm always impressed by Amazon's ability to rapidly deliver features.