Aleph released the proof-of-concept implementation: https://gitlab.com/alephledger/proof-of-concept ! I helped writing it, so this is a bit of a brag.
Transaction validation time was ~6s with 256 machines all around the world, so pretty nice. Since then, we have been working on a proper implementation in Go (this one I am even more involved in), but it'll take a while before it's published.