If someone wanted to make a batch of good quality 19800 or 21600 bph movements with the same hand sizes, date position, and dial foot location as a 15xx rlx (with quick set) it would probably sell. It would not have to look like a rlx, just act like one. Also make it quick set without a 'click' in the date setting position, just find the date set position by feel and make it hack or not hack by removing the hack lever like an ETA.
Make a GMT too!
I can't remember having an ETA 2620, I'll hunt one up.
17jewels.info: ETA 2620R