google has been changing how indexing works so you need custom indexes less often. if you app does not need them, then no index.yaml file will be created during local usage. this is OK as long as you have tested each query you have built that will run on production.
about the text property, from http://code.google.com/appengine/docs/python/datastore/typesandpropertyclasses.html#TextProperty "Unlike StringProperty<http://code.google.com/appengine/docs/python/datastore/typesandpropertyclasses.html#StringProperty>, a TextProperty value can be more than 500 characters long. However, TextProperty values are not indexed, and cannot be used in filters or sort orders."
