Delayed confirmation for below threshold transaction amounts

This might be a bit too messy and I'm not sure how much the protocol would need to be changed.

On a per node basis, transactions under a certain amount could go unconfirmed until some condition is triggered. This would at least force the current attacker(s) to rethink strategy.

The hard limit on what the condition would be is the received funds being required for a send. I'm sure a more lenient solution exists.

Since being able to send stupidly small amounts of Nano for free is part of the charm, I would propose splitting accounts into balance and pending balance so at least users have an idea of how much they own. I guess this would increase block size by the size of whatever datatype is used to store balance unless an 'off-block-lattice' solution is preferable.