Is it possible to have one menu bar while having displays as separate spaces in Mavericks? The Mavericks feature "Displays have separate spaces" is nice except for one thing: With vertically arranged displays, you need to aim for the menu bar in the lower display. 
This breaks the primary advantage of having the menu bar on the top of the display, which is that one can just throw the pointer upwards, and it will hit the menu bar and stop. (Fitts' law.)

Is it possible to have the best of both worlds: Separate spaces for my displays, but only one menu bar, located in my main display?
There's no built in function afaik. 
However - even if you manage to hide the menu bar via terminal magic (don't know if there is) you will still face the issue that windows can't lap over the monitor (since windows can't lap between spaces), you can only move the complete window to one space/monitor or the other