Google has recently announced the Java version of Google App Engine. This release also provides an Eclipse plugin that makes developing GAE applications with GWT easier.
See details here: http://code.google.com/appengine/docs/java/overview.html
Of course, it would require you to rewrite your application in Java instead of python, but as someone who's worked with GWT, let me tell you, the advantages of using a modern IDE on your AJAX codebase are totally worth it.
