(Note: This is a single-purpose sockpuppet account.)
Idea for airtight coin anonymisation, based on the fact that freshly mined blocks are the only truly anonymous untraceable blocks.
Create a TOR hidden service that resells virgin coins on consignment, to those desiring premium anonymity, as a moneymaking business. Virgin coins are those where the coins haven't been spent from their generation transaction, and only come in multiples of 50.
Here's how it would work. Someone who wants to buy an anonymous block could come along and purchase one at a premium (example: 55 BTC, or whatever price the market demands, they could be sold with bids and asks). That premium would be shared between the miner who provided it and the site.
One way this could work is if the site generated pre-seeded wallet.dats for miners they can use for mining, and the hidden service keeps a copy of all the private keys. For miners it would be a foolproof opportunity to make a few extra BTC: whilst they mine in one of these wallets, their coins could be sold by the hidden service when needed, available the moment they are mined. If the hidden service sells an anonymous block, 50 BTC just disappears from a miners mining wallet, and gets replaced in another wallet belonging to that miner in full, plus their premium.
These freshly mined blocks would be completely clean and have no transaction history. They could be used for cashing out proceeds of suspect activity, or whatever.
That way, the service could spend the coins directly from the miners wallet when bought without "virginity" being tainted by transferring them into the service, and also gets around the fact that it's difficult to choose which coins you're spending out of the current client when you do a transaction and have lots of coins.
The site would mix up the "dirty" coins before they went to the miners whose clean blocks were purchased. Miners would receive the mixed up dirty coins, in the process they would just get more of them.
Presumably these miners don't care what coins they get, they just want more of them, and they probably figure that any investigation that followed the money to them could be dismissed the same way if they were running a TOR exit node and activity got followed there as well. The answer would be the same as with TOR: "sorry sir, it's not me, I’m just doing a service to help bring privacy and a voice to oppressed third world countries". The risk and the hassle factor would be priced into the purchase price of an anonymous block.