Ah, pre-signing various variants. I don't like it much and it'd be nice to try to figure out if it can be solved differently but from first glance it looks like it's at least better than the current situation.
Discussion
You know, I've actually had people send me pre-signed txs at multiple fee rates before when they wanted to transfer me large amounts of โฟ and wanted to give me the option of choosing what fee rate to pay.
It's easily automated; the code can do all the hard work behind the scenes.