I was thinking that we could try the Parallel Blockchain. I know in Nxt community, CIYAM had an idea to implement the PB. However, CIYAM's PB idea was not in line with the specifications of CfB. I wonder if we can take a look at CIYAM's idea and invite him to NFD to develop the PB if it is a good idea. It seems Crypti is working on a PB project (the Crypti guy seems working on a Nxt related project before - https://bitcointalk.org/index.php?topic=636676.200)