Coin Request Module Just a simple input box to request payout coins somewhere on the dashboard/payout section. You can even scrub it against a list of known US exchanges to see if the coin will be supported and if not just display a banner to let the user know its a 'no go', otherwise email yourselv...

You could setup a smart contract to run the exchange through Uniswap. Customer is paid in ETH (much like how the Coinbase USD is paid in BTC) then at threshold it would send the ETH to the SC to exchange. The challenge is the fee. Users would have to be willing to sign up for a "flex fee" ...