This is a really good article that can get you started with this idea. You would have to develop your own solution but a lot of good ideas here.
Summery of a programmer's usage here: http://simonwillison.net/2003/Nov/26/discoveringBerkeleyDB/
Some Docs here: http://pybsddb.sourceforge.net/reftoc.html
Super fast but if the server dies so does all your data...