It seems like a pretty useful feature one of the big boys could offer to differentiate themselves. Or I could see a new entrant in the domain seller space marketing this as a main feature.
But it only works if it has significant compliance. If a new entrant offers the service, there's little reason for other places to implement it, because only a tiny percentage of their customers will be using it. And the big boys have a disincentive because they already offer things like email and web hosting. Making it easy for people to buy those services elsewhere will cut in to their revenue.
See @matthewaveryusa's comment above[0]. Looks like it already exists and is supported by GoDaddy, Google, CloudFlare, 1and1, and others. Still reading the spec but it looks pretty good.
