Much cleverness:

In this way, I was able to put together a geographic bounding box query, on top of Google App Engine, using a Geohash-like algorithm as a storage format, and use that query to power a FeatureServer Demo App Engine application, doing geographic queries of non-point features on top of App Engine/BigTable. Simply create a Geoindex object of the bounding box of your feature, and then use lower-left/upper-right points as bounds for your Geohash when querying.