Idea: a permissionless mining pool using a coinbase tx to a temp address, and have a pre-signed large payout tx from there. @OCEAN pool pays out some miners directly from the coinbase transaction, but they have to play some tricks, as the size is limited. IF we had covenants, it would be possible to commit to an arbitrary large second transaction, but we don't. Would it be possible to create a large payout transaction spending the coinbase, pre-sign it, and have a single-output coinbase? Miners are given the pre-signed transaction, and can verify that they would be paid with this block candidate. The pool or any miner could submit the payout transaction in the event a block is found. A malicious pool may try to spend the temporary coinbase output in a different transaction, so there is some trust needed.