Is the guy also working on de-anomyzing darksent(d)s?
No, he stumbled upon it whilst working on Ring Confidential Transactions for Monero. Perhaps if a bounty was offered he would try.
Maybe we should set up a bounty to be paid via budget proposal if anyone succeeds.
I think there still is a standing bounty. We need to verify if it still exists?! If so, we need to put it up on Dash.org