Two years later, Gavin still won't answer this question:
https://twitter.com/anonymouscoin/status/471177928097554433
https://twitter.com/anonymouscoin/status/471748516323528705
https://twitter.com/anonymouscoin/status/471177928097554433
https://twitter.com/anonymouscoin/status/471748516323528705
I'll break my "don't feed the trolls" rule:
You need two things to get private bitcoin transactions:
1) An anonymous connection to the Internet. Bitcoin Core does a good job of this, working nicely through Tor and/or as a hidden service (thanks to Pieter Wuille for writing that code).
2) A privacy-aware wallet.
The Bitcoin Core wallet needs to be completely rewritten, not just for privacy but to get rid of the Berkeley DB dependency, implement HD keys, implement multisig, CoinJoin, etc etc etc....
Nobody has stepped up to do that, so it hasn't happened; in fact, we are going in the opposite direction, moving wallet functionality out of Core (and we might eventually drop wallet functionality entirely to concentrate on transaction validation and blockchain handling).
Why do you ask?