Due to "popular" demand, I have created a BIP for cross chain atomic transfers.

Unlike the previous version, this version only requires hash locking.   The previous version required a "selector" transaction based on if statements.
    OP_HASH160 OP_EQUAL_VERIFY [public key] OP_CHECKSIG
    OP_HASH160 OP_EQUAL_VERIFY OP_N [public key 1] ... [public key m] OP_M OP_CHECK_MULTISIG