[toomuchtodo]

> Are you proposing their equity also be taxed "at rest"? How would that work?

Same way property is taxed. A taxing authority sends you a bill (based on duration of ownership), with the tax rate set by legislation. In this case, the custodian of your equity would send you your bill, with a copy sent to the IRS. I don't believe who accepts the payment needs to be defined at this time (although sending payments directly to the IRS or through your custodian are both trivial matters).