There is a 10x24 that was sold under the Jet brand and several other brands that is a real full function lathe. It has a standard 2 lever quick change gearbox that cuts its full range of Imperial threads without gear changes. It also has back gears that take it down to 75 rpm, a tumbler to reverse the feed/left hand thread and power cross feed in and out. It’s much heavier than most sm bench lathes at 700-750 pounds.The gear box is primarily for the power feed, it will do a few different threads on a set of gears, so potentially you could get lucky and find your most popular threads fit into a set of gears, but you will not get away from change gears.
This is going to be the case with pretty much anything in this size class, you have to go vintage USA or 12" and larger to get a full gear box.