In the Airgapped Wallet Community we also have been investigating solutions, in particular as current common practice is is reuse the same xpub for all multisigs, for instance [90081696/48'/0'/0'/2'] xpub6DYLEkDfCdHzh5FHGHDJksQvFqu6kYANa1sfo6fA8n5ZWkSwyCRVVzyq9LY2eNGB6T9BKDeGJp2ZarjRZHd7WB95nSaFEDhFMK6zSV6D49b
I don't think reusing XPUBs inside different multisig wallets is a good idea... For starters, loss of privacy in one wallet will immediately affect privacy of other wallets. I think multisig wallets should be completely firewalled from each other. That means one unique XPUB per wallet. This is what we have been doing with the Nunchuk wallet.
We’ve also have been looking into multi round commitment scheme, but wanted to align the UX so that it would work like to musig for users. Discussion on it is scattered, for instance
Nothing got as far as your version though.
So Concept ACK from Blockchain Commons. Less clear on your specifics though. We will review.
Note that we are releasing a descriptor & multisig centric iOS and Android reference wallet soon so solving this correctly and having interoperability with others is very important for our roadmap.
Thank you and good to know ! Look forward to solving this correctly as well.
Best,
Hugo
— Christopher Allen