You said that you are commuting, do you ride in cycling shoes or do you wear some form of athletic shoe with a flat pedal? The reason for asking is that when I commuted, I rode with flat pedals and found that I rode a lower seat height than my road bikes due to a different foot position. I tended to ride with my the pedals more centered under my midfoot, just felt better pushing the pedals that way, but it definitely means a lower seat height.
I am 6'0" with a 35.5 inseam, not as long legged as you but still on the longer side. The best fitting vintage bike I owned was a Trek 560 in size 60cm, I believe. It had a shorter top tube than my other bikes. I bought it in 85 and wish I still had it!!