This was referenced in a recent mailing list post about removing dust UTXOs periodically: #10642. My problem with this is that dust is relative - today's dust won't be tomorrow's. But, it does present a DoS vector via the utxo set. This is mostly a function of how the utxo set is stored/retrieved though. Perhaps some redesign of the utxo set storage/retrieval would prevent dust from becoming a DoS vector?