Stripe Admin Payments

If a customer has a Stripe account on file, the ability to process a payment on that account from the admin screen. This is beneficial in a couple of scenarios.
1) Non-standard payments that occur on a semi-regular basis. A client authorizes up to $300 in work be billed when completed.
2) A client receives an invoice and calls to ask to process the payment. Being able to “add a payment” and have it process via stripe (or other gateways) would be great.

Implementation would be best on the edit invoice screen. Maybe a “Pay now with linked [Stripe] account’ button or other payment gateway.