Embeddable Enterprise Collaboration (Microblogging) Engine

Question

Short Version (tl;dr):

Is there an open source or commercial engine that provides embeddable collaboration and microblogging functionality?

Long Version:

I am creating a niche application that has need of this functionality and do not want to reinvent the wheel. The following are must have requirements:

• Data API only. My application is SaaS, and I want to build the functionality around the data. This eliminates most of the offerings out there (facebook, salesforce chatter, yammer, present.ly, teambox)
• Does not require use of a built-in front end. I really just want an engine that will take care of the storage and events, and gives me a means of querying. Requiring the use of a specific front end renders it useless for embedding into my app. This eliminates everything else I have found (status.net, Yonkly, Jaiku)
• Beyond standard updates and replies, can handle custom events. For example, if I were embedding this into an logistics application, I could have the engine handle events like "shipped", "received", and "cancelled".

Beyond this, there are several nice to have features that a framework would have:

• Should not require a specific platform or server technology to run (i.e. something like a RESTful API would be nice)
• Should be message based so that commands that affect its state can come from any source
• Should encapsulate its own storage so that external resources are not necessary (i.e. no database needed)
• Should have pluggable extendable UI components/widgets for web, mobile, and desktop clients
• Should have search and retrieval APIs available for many languages/platforms

It seems that someone out there should have this already, or at least be in progress with it. Please point me in the right direction.

Answer 1

Since nobody had any answers and continued research did not find anything, I created a solution on my own called Collabinate. Updates can be found on Twitter, and the project itself is hosted on GitHub.