I like this idea, although until any functionality like this is created, you may have some luck using roll-up summary fields of opportunity products on the opportunity itself. That calculated field can be added to the deal mappings, so at least you get some data appearing there.
You’re at the mercy of the SUM/COUNT/MAX/MIN limitations of those fields. So while you can’t get the specific products added to the deal, you could get things like product counts to HubSpot, and the like. This is not the same as your ask; it’d be more of a does/does not exist sort of thing, but it is an option available now.