Charles VII? Franz I?
How about this? Charles VI has no children whatsoever. Maria Josepha inherits. Her Wettin husband is Emperor and then so are their descendants.
Franz I is still Habsburg (Habsburg-Lorraine), though yes, forgot about Charles VII, though he was the only non-Habsburg Emperor in a period of about 400 years, though this was more a side effect of the War of the Austrian Succession than anything.
Franz I is still Habsburg (Habsburg-Lorraine), though yes, forgot about Charles VII, though he was the only non-Habsburg Emperor in a period of about 400 years, though this was more a side effect of the War of the Austrian Succession than anything.