Nice post, you should have a look to BitShares, SteemIt and EOS white papers which are all based on Delegated Proof of Stake (DPOS).
Each 3 seconds a new block is created, through 20 witnesses. DPOS is using pipelining to increase scalability.
Those 20 witnesses generates their own block in a specified order, that holds for a few rounds (hence the pipelining), after the order is changed.
It is easy to increase the scalability of this schema, by introducing additional witnesses either by increasing the pipeline length or using sharding to allow to generate in a deterministic/verifiable way few blocks during the same epoch.
There are additional details in this post from Dan Larimer:
This is the missing white paper and analysis of delegated proof of stake (DPOS). The goal of this paper is to provide…steemit.com
You should try SteemIt, it is really great fun and it has a large cryptocurrency community that pays well.
Wish you the best.