Yeah, I was looking at the 977e, I considered buying one and going with a 12s set up. But that would require a kotronics esc or something similar to handle the stupidly insane power, not to mention an airport runway to open it up—which I don't have access to.
As for the 747e project, I had heating issues when I tried a 4s on a 550 4700kv motor. Gearing was the key there; for as soon as I jumped a tooth on the pinion from 27 to 28 (55 spur) magic ghost rose from the esc. But with a 1/8 motor, I don't really have much heating issues, and thats with a 35t pinion and a 6s.