Joe you might like an old Necchi Nora or some such but they are sorta like a Kenmore.
Elna SU is nice and would be a challenge for you
I'm sure Pfaff, Bernina and Viking would keep you busy.
You have been working on old fairly simple machines so far - that is NOT a bad thing...
I think this time of year is depressing - no Christmas to look forward to - spring still seems a long way off
not enough sun or warm weather... blah blah blah...