Anoncoin <https://anoncoin.net> will soon be implementing the Zerocoin
<https://wiki.anoncoin.net/Zerocoin> protocol. Which has long been
considered the true holy grail of cryptocoin transaction anonymity IMHO.
Even more anonymous than the Ring-signature
<https://en.wikipedia.org/wiki/Ring_signature> technique of the Cryptonote
protocol coins like Monero. The Anoncoin devs aim to have it on their
test-net by October the 15th
<https://bitcointalk.org/index.php?topic=227287.msg8997381#msg8997381> and
their main-net by November the 1st. They hope to manage to implement
Zerocoin in a trustless manner using an RSA UFO's
<https://wiki.anoncoin.net/RSA_UFO> technique.

In the future though with Bitcoin side-chains it may be possible to have a
Bitcoin Zerocoin side-chain to move bitcoin in and out of in a trustless
p2p manner. Although it currently looks like we're still way off Bitcoin
side-chains yet. So even further for a Bitcoin Zerocoin side-chain.
Although Anoncoin are still on target for putting Zerocoin on their
main-net by November the 1st.

MH