Domain Events Implementation

We are starting DDD, and we need to implement domain events (DEs). We are thinking about "developping our own system" vs "prototyping an exiting framework". We know some things about DEs. But we need to have some real-life feedbacks about what features should be expected from such a system, before taking a decision :

• Should DEs be stored and duplicated in each domain from a centralized event-store, before being consumed (for maintenance and logging purposes) ?
• Do domains pick up events from the centralized event-store (if none), or do we need some kind of orchestrator for dispatching DEs ?
• If we use a relational database for storing domains data (we know we should ignore it when desiging business logic), does that relational database fit for DEs, or should we prototype a NoSql database ?
• Do we need to implement some tools to ensure events are well propagated into target domains ?

I know there are many questions here, to summarize I would just ask :

Based on your experience, what are the key-features we can expect from a "theorical DEs system" ? Have you develop your own implementation, does-it make sense ? Does a service-bus meet our needs ?