I can't speak for anything other than the Singer 112W, which is a double needle machine, or any other double needle sewing machine..................BUT This is the same machine as a 111W. If you change the needle bar, it can be a single needle machine. Once again, ..............double needle machines are meant for one specific operation in a factory setting. You could only use one side of the double needle machine to sew flat sewing, but there are no welt feet or any other feet made for a double needle machine which is intended to do one specific operation.
In short: NO, there are no double needle sewing machines that can do everything you need them to do to sew a car interior.
No one lives forever, the trick is creating something that will.