Alright, I suppose once in a while I need to earn my keep and at least try to help instead of being sarcastic.
If you haven't guessed, my truck has a (problematic) auto transmission in it. It has been removed multiple times, always put back with different little... . quirks.
See, one of my issues was, as JLeonard pointed out, the linkage. It wasn't aligned right when the transmission was put back in and I couldn't get the truck into reverse. Basically, all the way up on the steering column shifter, it would hit the stop before making it to park. From there, it was almost impossible to hit reverse, because it wouldn't fall into the slot in the right place, thus not letting me into reverse. Which brings me to my next point. Have you actually seen/tested the starter, or are they just telling you it's fried. What happens is this: the linkage not adjusted properly, causing your no reverse problem, but also you can't get it into park... . well... to an extent. This is where it trips people up. Itll go far enough to actually put the transmission in park, and lock it from rolling, but not far enough to actuate the switch that tells the truck that the transmission is in park. Obviously you can't start it in gear, so you turn the key and nothing happens. Lights come on like they should, glow plugs fire... . everything happens as it should leaving just the starter to do its job, and it won't. The truck won't let it. To anyone else, you have no reverse and a burned out starter.
Try this, put it in park, and smack the shifter upward with your palm. Give it a little gusto, it can take it. Nice and hard. Now turn the key. Watch the amazment in the eyes of the seller as his "burned out starter" fires that bad boy right up. If that doesn't work, a truck will start in neutral. Sounds too simple to work, right? It is. The same problem you had with the truck not knowing its in park will apply to the truck not knowing its in neutral. Neutral is a little easier though, because sometimes no matter how hard you smack it, you can't quite reach park, but unless its really out of wack, you can find neutral. This is probably what you'll have to do. Turn the key as shifting from reverse to drive. You may have to go back and forth a few times. HOLD THE BRAKE!!! I know it sounds like itd be awful to do, but doing it once to test a theory wont hurt anything thats not already broken. And since you'll be holding the brake, the transmission shouldn't budge either way, so you really shouldn't grind any gears or anything.
I had to start my truck in one of these two ways for about a year until I blew that transmission and had a new one put in. I'm not gaurenteeing this will work, but it sounds like the symptoms. Let me know.