Has anyone ever proposed adding a Zerocoin or Zerocash sidechain to Monero? The idea would be that, by default, one would get the well-tested privacy of Cryptonote, but could optionally use the obfuscation of Zerocash when they were conducting a transaction they felt needed to be particularly secure. I think this would be useful because it would give users an extra layer of choice in terms of how secure they want their anonymity to be, versus the computational cost and the riskiness of the crypto.

How difficult would this be to implement, especially once Zcash gets released and tested? Would it be possible to just copy pieces of the cryptography, with perhaps a few changes, or would Monero's design require a fundamental change to how the sidechain is set up?

~ Lexi