Sounds like this can be done using Dash data contracts. While the money and control side is decentralized, I'm not sure which path is best for the front end, except the obvious of creating a standalone app.
Hello there! By the way, do you think the idea is of benefit to nostr ecosystem? Bitcoin and Bitcoin Cash also have their crowdfunding softwares. For instance for BCH it's flipstarter. I think two transactions are signed. One to send to me and the other back to the sender. Then one of these is broadcasted. But each of these softwares are coin-specific. I would like to have at least 3 coins in mind. Like BTC, BCH and XMR.