We are actively working on object storage (Swift), and contributing back
CTO & Founder, Nexenta Systems. I'm running both Cinder and Swift projects at Nexenta. On the object storage side, we're implementing and keep supporting the latest Swift on top of ZFS local filesystem. Also, gradually but surely moving forward a number of inventions that will make it more effective, as far as performance and deduplication (search nexenta.com for CCOW and Replicast).
On legacy file and block storage side, we'd first implemented the entire https://wiki.openstack.org/wiki/CinderSupportMatrix; second, at the latest Hong Kong OpenStack 2013 summit suggested (backup/replication) CRESS improvements - codename that stands for Cinder Replication Extensions for Stateless Snapshots. The idea is to implement CRESS first as an Nexenta extension, and then work with the community to propagate it into core API.
For more details, see my linkedin and nexenta.com pages..
I'm involved in the following OpenStack projects: Nova,Swift,Keystone,Quantum,Cinder