Following Mike's lead, I purchased a pair of the Baja Squadron 4300 lumen "Pro" lights with spot beams. Holy **** are they ever bright! Our airplane hasn't flown yet but I have done testing on our rural gravel road and on our local airport's runway. This is a somewhat rural airport with zero night lighting. When the runway lights are off, there are no lights to be seen, other than the rotating beacon.
In the testing at home, our power poles are 100 yards apart. I have no trouble seeing with sufficient detail to make out an animal four poles away. The two lights completely fill the 66' wide road right of way. Both sides of the road are completely treed so from this test I wasn't able to determine how much wider the beam might have been at 400 yards.
At the airport I powered the lights from a small battery and pointed them up the runway to the button from the taxiway intersection, about 400 feet. The two lights completely illuminated the runway at that distance - it was like daylight. I turned around and faced down the runway and had no trouble seeing the runway, it's markings, the transition from faded grey asphalt to gravel along the edge, etc, all the way out to and beyond the 1000' mark. It was hard to tell at what distance the light faded to a level below that which would allow the shape of an animal to be discerned, but I can say from experience the single 4509 landing light in the certificated aircraft I fly has never lit up the runway and the surrounding ditches like these Baja lights do.
Since we have a high probability of encountering wildlife on the runway, these lights seem to fill the bill when it comes to "see and avoid" on the ground.
Now for the down-side... I think I'm going to have to install a less intense taxi light in the engine cowl as I suspect these Baja lights in the wingtips will not be appreciated by other pilots during ground ops.