Hi Dan ! Hi Greg !
Dan, you've said you have been able to run the code with an MPU9250 + Arduino MEGA ?
I've just tryed the same, but I'm unable to make it work 
I've been trying for months now, not every nights, but...
Would you tell me which code you used ? which libraries ?
I'm afraid there's just a little thing different and nothing works...
Tonight, I've tryed an i2c_scanner with the same arduino mega and MPU9250, with a windows 7 computer runing arduino 1.0.6, and with a windows 8.1 computer runing arduino 1.5.7.
In the first case, I get the address 0x68, and in the second case, I get 0x69 !?? Strange thing !
Would you give me your complete configuration so that I can do exactly the same ?
Thanks a lot for your help !
Sylvain