How to use N-channel MOSFET as high side switch (non-buck switching)
If the application permits, you can use an isolated power supply (12V or 15V) to create the gate driver voltage, then use an optocoupler to turn MOSFET ON or off.

You could use a photovoltaic MOSFET driver (usually used for SSR)
For example the VOM1271: VOM1271

Use a automotive high side switch (it contains MOSFET and driver protection features and diagnosis), search Infineon and ST, but honestly it might be difficult to find one that works at 80V 
Another example: smart high side switches