I've got a Power Drive on the front of my boat.  I'd like to take about 9 inches off the shaft.  Has anyone done this?  Are the wires in the head connected via fittings, or would this require splicing wires (which I won't do)?

IIRC, they use push on connectors in the top of the motor head.  

I had a Max. shortened from 62 down to 54. Buddy removed head and outside shaft, took the inner shaft out of the motor shorten the motor end and re thread shaft. The threads are standard pipe thread and he use 5 minute epoxy on the threads.

Worked for 3 seasons.

I also read about this guy that need more length 78" and he threaded 2 shafts together.

Garnet

I just took 10 inches off the shaft.  That was a pain in the butt.

The head is held on by a cross screw that passes through the center of the shaft.  It passes between the wires that come up from the motor into the head.  There is no inner shaft and no theads anywhere.

I removed the top half of the head and disconnected the wires that, as Cart stated, were held together by male/female connectors.  I took the head off, and it ain't easy getting the screw out.  Once the head was off was I marked off 10 inches.

I was intent on cutting the shaft while leaving the motor on the shaft to minimize breaking any water-proof seals (if there are any).  I used a pipe-cutter and started to turn.  That friggin' shaft has some thick walls and that carbon fiber is hard.  I was making next to no head-way so I started to carefully saw with a hack saw.  That was an effort in futility, too.  So I got out the grinder and and a silica disk and was able to carefully cut the shaft off.  

Then I leveled and beveled the end so it would slip back into the head more easily.  I put the head on and drilled the cross hole using the holes in the head as a guide.  This has to be done VERY carefully since the wires are still in the shaft.  

I shortened the wires, put new connectors on and hooked everything back up.  

The job is easy in concept, but hard to execute.  Cutting the shaft is 90% of the job.  If you do it with the wires still in it, you have to keep cutting around it until it comes off so as not to damage the wires inside.  And you have to make sure that when you put the head screw back in it passes between the wires in the shaft.  There isn't enough room for both of the wires to be on just one side of the screw.

If I was to do it I'd take the 10" off the top. The threads are on the other end. Buddy removed motor and wires complete then shorten the threaded end and re did the threads. Cutting the shaft was easy chop saw.

Garnet

I was a little scared to try this but once I did it was not too difficult. Take the top of the head off, unhook the wires. Take the head off. measure how much you want to cut off. Find a metal pipe that just fits inside the shaft and slide the wires through it to protect them. Cut the shaft, shorten the wires, drill the hole in the shaft for the head and reconnect everything. It was really not too bad. I would make sure though that your warranty has expired because this would probably void it unless you had a minn kota service man do the job.