state of 'atomic cross-chain trading' in 2016 Much of the information I've come across is a bit dated, 2 years or so. 

For instance, this other question, this thread on the forum. 

It seems like Interledger is trying to implement, more or less, the described protocol of ATXC, is that right? 

Other than that are there any actionable implementations around?
Interledger's protocol is not atomic swaps. Their model is not entirely trustless either.
There are actionable implementations like MercuryEx but not used because:
a. transaction malleability fix is required
b. discovery problems in a decentralized system