Ok, I thought more in terms of capacity and size but if you want to expand:
727-200 connecting to a 727-100
Bac 1-11-500 connecting to a -200
Caravelle 12 connecting to Caravelle IV
Tupolev 154 connecting to a 134, nahhhh
Where in the world can you still do that? But here in the good ol' USA you can still fly DC-9-30/40/50's on Mainline services.
FYI just came back on the same routing with two CRJ-200's- Made the DC-9-50 look like a spaceship!