Referring to Unicycle Electrical block diagram, both Control Board(CB) and Drive board(DB) needs 12V source.
So what options we have.

1) Method-1 Tap from the 60V battery pack.
Pros: > Available from the battery, no need of extra electronics.

Cons: > Tough to tap from a battery pack..( Alex is it ??? )
> If not done properly leads to ugly looking wiring and loose connections..!!!!
> NO Isolation between CB and DB.
(Alex is it really required, need to validate. My opinion, if routing of tracks and wires of the entire system is done properly it would not be required. But generally its preferred.)

2) Method - 2 60V to 12V Non-isolated buck converter
Pros: > No need to tap from the battery.
60Volts from the battery is converted to 12V and fed to both CB and DB.
Cons: Still no isolation between CB and DB.

3) Method - 3: 60 V to 12V isolated power supply and 60V to 12V non isolated power supply.
Pros: > Isolation between CB and DB is achieved. :-)
Cons: > Extra hardware and cost (Not too much. Worth it for the piece of mind.)

4) Method - 4: 60V to 12 dual isolated power supply.
Pros: >Still Isolation between CB and DB is achieved. :-)
> If designed properly this method would cost us little cheaper compared to Method-3. :-)
> This keeps the 12V line going to the Driver Board also little cleaner.
Cons: > Dont think of any compared to Method-3.

My opinion
If isolation required between CB and DB I prefer Mehod-3 or 4.

If isolation NOT required I prefer at least Method-2, as a worst and last option method-1.

Whats your opinion folks..????