A way to create contracts and have clients sign them through the Business App portal.

I envision having it available in Partner Center where you can create contract templates and then customize them within a client's Account Overview section within Prner Center. Then sending it to users assigned to that account would email it to them with a button that brings them to their Business App. Probably a new section called Agreements or something. And they can sign it digitally. And no one can tamper with the "document" after that.

This could potentially be associated with invoices and/or subscriptions.

It would circumvent the need for 3rd party apps like DocuSign, etc. and add to the whole business solution ecosystem.