There was an interesting production-grade event store released recently which fits the described use-case: http://geteventstore.com http://geteventstore.com Ba

There was an interesting production-grade event store released recently which fits the described use-case: http://geteventstore.com http://geteventstore.com Basically, you store all of the data as events (event sourcing) and create separate query views (projections) which are populated from event streams.