Tracking the Bitfinex hacked coins
This is possible. It also may sound good on paper, but the implications are horrible.

Think of it. 100 thousand bitcoin. 0.5% of all coins will be rejected. This is out of 21 million. Out of the current 15 million, maybe 0.65%. That's hugel

If a hacker also wanted, he could move the coins into multiple mixers and deposit them in and out of Exchanges, as they're off-chain. Hacker could even sell a couple.