While blockchain theoretically unlocks "triple-entry accounting", hashing all accounting activity to a public ledger is problematic for businesses. 

Application of ZKP feels like the solution, but trust of the tech and practical implementation is a massive hurdle.

Has anyone seen interesting ideas on this front?

(1/2) I don't think its adoption is as big of a hurdle. When corporate GLs were solely on-premise the idea that CFOs would move their financial data to cloud-based solutions was ridiculous. However the value proposition of accessing your data and scaling your finance organization globally was clear.