Can the KK controller board produce stable video?

The KK board can produce excellent results, but you have to work hard to get the best out of it.  You need a well built multirotor with well controlled vibration.

But the real secret is to turn the gains on all three gyros right down and use your flying skills and not the computer!

When the gyros are adjusted to just below the point of oscillation, you can get good stable results in light winds and low forward flight speed.  But once the wind gets up and the speed of the craft picks up, you will notice that the video becomes bumpy and uneven.  Turn the gains down as much as you dare and fly it!

Note: KK board firmware with higher refresh rates (such as V4.7 Quadcopter X mode) exhibit less instability at higher speeds, but fast flight is still improved when the pitch and roll gain is backed off a bit.

Tricopter
Based on the RC Explorer V2 design with ball raced yaw mechanism, NTM motors and new camera mount design. 

2200mah Turnigy 25C 11.1v (6 minute flight time)
Motors - NTM Prop Drive 28-36 750KV / 265W
18 AMP RC Timer speed controllers
HK KK V1 board V1.6 firmware
10x4.7 SF props (Genuine APC)
Turnigy 9X radio with ER9X software and FrSky module
FrSky V8FR (HV) receiver

Yaw mechanism.

GoPro mounted on a laminate of 1.5mm fibreglass board and 3mm ply bonded together with epoxy.  This is mounted to the frame with dense rubber foam sandwiched between velcro.  Finally a loop of silicone fuel tube (not shown in this picture) is wrapped around the mount and frame which applies a small amount of pressure to stableise the velcro joint.