There are no solutions like that. The only solution is don't use cut & choose except where checkpoints are trusted, or develop the zero knowledge black box solution.
The attack is more general and it doesn't specifically attack the cut-and-choose system, I think.
- Offer to sell A altcoins for B Bitcoins to 1000 people
- Perform the atomic trades
- You now have 1000*B Bitcoins and lost your A altcoins
- Victims made sure there was 10*A worth of hashing confirmations on their transactions before moving to the next step
- You spend 50*A altcoins to buying hashing to rewind up to 50*A worth of blocks, which is more than their protection
- This rewinds history and your 1000*A altcoins are now yours again
A defense against this would be to mark the multisigs that are being used as anchors. Rather than 2 of 2, you could use 2 of 3 with the 3rd key being a standard value.
You can then set k based on how many trades are happening on the altcoin chain.
As long as cross chain transfers are much smaller than real transfers, then this is less of a problem.