I've open sourced two Rails plugins that facilitate building distributed Rails applications. Use_uuid integrates UUIDs and schema less attributes into rails models. Acts_as_distributed replicates state changes to model objects to a queue so they can be distributed to other databases and applications. Both of these plugins are currently in production in newsforwhatyoudo, and are tested with Rails 2.2.2
Rails is a great framework, but its not simple building a distributed application. These are two small steps towards making it easier. I'll be talking at the SF Ruby Meetup about how we use these plugins on May 13 - see the meetup link here. It would be great to collaborate with other developers on building out a collection of plugins that enabled all the key portions of distributing applications in an integrated way.