For me it went into the multi-node direction, where I'd use Ceph anyway (or build on-top of an existing solid distributed database) if I needed it.

Also think there is an abstraction mismatch with the object stores that store the objects with a 1:1 mapping into the file system. Obvious issues are that you only get good listing performance with '/' as delimiter and things like "keys with length up to 1024 bytes" break.