Other things (not very common, but easy to check) that can cause a no-crank are shorted out v-reference sensors. You can try cranking w/ the EGR valve, MAF sensor, GPCM, ICP sensor , IPR valve, EBP sensor all disconnected (to name the major players).
Another test is to see if fuse F2.22 circuitry is a giving you a problem (visually check the fuse first) is to unplug and crank w/ the middle PCM plug disconnected. This is PCM plug C13881c (it feeds about half of the engine sensors, including the fan clutch, EGR, GPCM, and the EBP sensor). F2.22 circuit also provides PCM power ... and problems this circuit will cause a loss of cranking. MAF, EGR, IPR, GPCM, and Fan Clutch are involved in that circuit via (these are all in the C1381c "middle" connector). C13381a contains the MAF and Fuel Bowl circuits, but it also contains the starter relay circuit and network communication, so it wouldn't crank w/ that disconnected. C1381b (end plug towards the front) is primarily the transmission controls.
As stated above, I wouldn't advise the average truck owner to mess w/ the range sensor.
Edit - here are several good reads:
04 6.0 won't crank...
no crank no start
Best of luck.