The Riak key/value store is extremely fast and reliable, but has limitations on the size of object that preclude its use for some applications. For example, storing high definition still images or video is difficult or impossible. Luwak is a service layer on Riak that provides a simple, file-oriented abstraction for enormous objects.
Not a FUSE interface, but still interesting. An it has both a synchronous and asynchronous API.
Original title and link: Luwak: Riak Library for Large Files (NoSQL databases © myNoSQL)