I thought I read someone ports Google's AppEngine to use HBase. Good idea but not quite. "Announcing A BigTable Web Service": "I then came up with the crazy idea to offer BigTable as a web service using App Engine. It would be an infinitely scalable database running in Google's datacenters. I spent my weekend learning Python and hacking together an implementation. Now I'm happy to present the BigTable Web Service. It models the API of Hbase—a BigTable clone. Now you can have simulated BigTable running atop App Engine, which itself provides an abstraction on top of the real BigTable."
What it actually does is use HBase's Thrift API on top of Google's BigTable or as they say BigTable as a Web Service (a RESTful one).