Yeah. ‘Working’ might be a generous description, but I implemented several working methods - like keyforamount, swapforamount, mint/bolt11foramount. I stopped when I was told it was a bad idea, but it greatly simplified the proof management and payment.

I hacked it all in nutshell Cashu mint.

Proof of work is in this branch below. Bottom line, I was successful in deriving the public/private key for any arbitrary amount and issuing the promises.