Something I'm just curious about (not that I'd try it), but I know how if you start a standard-shift truck while it's in gear and you're not pressing the clutch, it'll lurch forward on you. But what happens if it's in a higher gear? (like 5th, 7th, or even 10th!)? Would it spring forward even faster?

I moved my truck once doing this, in about 4-5th gear. This was while bobtailing. With a trailer you probably wouldn't even move.

I've had to drive trucks with broken clutch linkage back to the shop a couple times.

I'd just put the trans in low gear, start the engine and off it would go, then just shift up from there. (without the clutch obviously)

When coming up to a stop, after downshifting thru the gears, I'd just pop the stick in neutral, then shut the engine off once the truck was completely stopped, then repeat the process to start off again.

So to answer the question, yes it will start off in gear (lo gear), but I've never tried it in the higher gears.

I would think that the starter wouldn't have enough torque to move the truck in the higher gears.

It does! I moved mine in 4th gear I think it was, because low gear was too low. My engine quit on me (air in the fuel system). Was the only way I could get it back into the shop.