We have our own custom checkout that works with Authorize.net and ties via API to our SAp B1 accounting system. We would like to work with Shopify on building a Hosted Payment SDK that will allow us to take our wholesale customer orders and flow them though like our other custom sites. We are transitioning from another well-known platform for 3 websites. The inability to automate credit holds and NET30 terms out of the box is a big limitation and a frequent need for a mid-sized wholesale company.
Since we custom-built our non-shopify sites including payment gateways with our API and we currently are tied into the Shopify API for 2 new retail sites we are thinking this could be a solution for us and allow us not to scrap Shopify as a wholesale option.
That said the form to fill our for Hosted Payment SDK seems not the exact fit based on the questions being asked.