It wont throw very far. The luminance of incandescent bulbs is rather limited.
Depends on the bulb. Incan bulbs can obviously be very good throwers in searchlights.
Too bad that guy stopped making videos. I used to enjoy his stuff.
How about making 20kw LED array instead? (Yeah, right, two frickin’ million lumens)
Good luck cooling it though 
Water cooled and a large radiator, If not enough then a second radiator. Problem solved.
Not really. There are much better light sources (much higher luminance) for throw. With a very large reflector you can hold a lighter into it and it will throw far. That doesn't make it good. Incandescent bulbs max out at around 60cd/mm^2 (melting point of tungsten). LEDs already go above 250. Short-arcs go to 5000. Single crystal laser phosphor might even go beyond that.