New proof-of-work schemes in crypto-currencies should ideally have optimized implementations from day 0, to prevent the situation described in the article where some people can mine much more efficiently than others.

To this end, I offer several bounties for my Cuckoo Cycle proof-of-work scheme, which David has helped refine, and which has yet to be deployed by any coin.

See https://github.com/tromp/cuckoo for details and a whitepaper.