The Skycrane has been used with good success in the Northwest US where they reside for logging operations. Again, if water is close by, their high recycle rate makes up for their low capacity. They are much more accurate and that makes up for some of their lack of capacity. In the Southwest US, the lakes are few and far between.
After cogitating the 747 overnight, it must be an engineering challenge considering the weight and balance issues of offloading tons of water. The C-130 used to experience transient CG out of limits during LAPES drops. The 747 will have to be configured with dump nozzles fro the forward tanks and the aft tanks so the CG doesn't wander too far off the chart. As Cyclic pointed out, if they pull it off, it WILL be impressive.
Can't wait!
PT
PS -Ever hear of the urban legend that recounts the story of the two guys scuba diving near the surface off the coast of Oregon? Supposedly they were swimming along one minute and the next minute the one diver looks around and his buddy is gone. Days later mop-up firefighters find a charred body of a fully equipped scuba diver in the blackened forest area that had just experienced a fire.
---A skycrane was supposed to be involved with that one.