Yes, Ripple was looked at, but it's been quite a few years and I don't remember much about what consensus protocol it had back in 2013. I don't think it was particularly interesting, or I think I would recall it.
From the BitShares point of view, the ability to "ripple" a trade across multiple markets was definitely interesting, and I'm occasionally surprised that the Ripple feature was never directly implemented in BitShares (although someone wrote an arbitrage bot on BitShares that did that, but pocketed the arbitrage rewards).
RE: The History of Delegated Proof-of-Stake (DPOS)