TOPIC:

Does anyone know off hand how tall I can go for handlebars without changing the cables and wires on an 81 kz750 Ltd 4 cylinder? 

What handlebars are currently on the motorcycle?  If stock, then maybe Flanders medium tall street bars
but I don't know if they're actually taller; they're just more comfortable than the narrow buckhorn/pullback bars. 
I had them on my motorcycle which is virtually identical to the 750H Ltd except for the wheels & brakes.  

1981 KZ650-CSR older pic with the Flandes bars. I have since installed Emgo Euro bars.

You could remove the handlebar clamps, pull the bars up until the cables and wires are a little tight and have a helper measure the distance between the bottom of the bar and the lower clamp surface. That would be the maximum extra height you could use. I suspect it is not much.

Here are the bars on it now. 

 

Would prefer so mini apes or something this is the style I’m going for.

Handlebars are hard to recommend. I really like Euro bend bars but I am short in the body. Your bars look wide, is there room to take an inch or two off each end? And maybe tilt them up a little?
I prefer bars that the grips aren't too high up, angle down and back so it drops your shoulders and elbows allowing you to relax more.
Here's euro bend bars on the 77' KZ 1000LTD.