I’ve just been reading about cross-chain atomic transactions here:
https://en.bitcoin.it/wiki/Atomic_cross-chain_trading
Seems like a great idea, are there any known implementations? And is the only reason this is obscure because nobody can make money out of it?
Malleability is one main issue.
Beside that it does not scale on the resource and engineering side.
To support 10 altcoins you need to run 10 times a blockchain engines like BitcoinJ. Both to implement that and to run that on a normal cpu will not scale.
Though to select 1 or 2 altcoins with special properties (like Monero or ZCash) for a double cross swap as alternative for a CoinJoin is something I have in mind for mid term future. But much else to do before…