.NET Web Service / API for BLOB/File Storage

I am looking for an API that performs functionality roughly analogous to Rackspace Cloud Files / OpenStack Swift, Microsoft Azure Blob Storage, or Amazon S3 that can be run on a Windows Server.

I am not speaking of all the add-ons including replication, etc, but an API that enables a similar RESTful API for the storage/serving (including Anonymous). Some examples of functionality I like, and would be missing if I rolled my own right now, a开发者_运维技巧re:

• Rackspace's Large Files support.
• Amazon S3's Root Document support.
• Microsoft Azure BLOB storage Page Blobs and Authentication.

Options like MongoDB's GridFS are getting close, but wouldn't quite cut it. RavenDB's "Attachments" functionality is pretty close, I understand it only supports up to 2Gb via the ESENT storage engine

Just to clarify, I'm not exactly sure what form this would take. I'm not looking for a pre-built product (which I don't see exists), but perhaps a stub of a project, an open source project planning to provide this functionality, people who might have developed their own similar solution in C#, etc.

We have RavenFS that handles that scenario, I think. It is a commercial offering, though.