This is just a quick post, but I've started playing around with "thrudb":http://code.google.com/p/thrudb/, and naturally, writing a ruby library for it. It's still incredibly rough. The indexing code is busted since I started testing with a mock manager class instead of the actual thing, so about all it does is saves and fetches records at the moment.

You can get the code from:

git://git.caboo.se/activedocument.git.

Note: I have an experimental json branch and a sample app to "pit the 2 data stores against each other":http://weblog.techno-weenie.net/2008/1/14/benchmarking-activedocument-vs-activerecord.