Question:
,./

Answer:
All of the major carriers that I've ever worked for Paid for DeadHead.(of course the mileage was off about 10%...but I did get paid for them, for the most part.)
The only time I did Not get paid for deadhead was when I drove for a few small ma & pa carriers & I was getting paid PERCENTAGE. (and I knew when I signed on that I was NOT getting paid deadhead.)
About the only time I've ever heard of a company drvr (that was on mileage pay) Not getting paid d/h was if the drvr went out of route or used an unapproved route.
Maybe his trainer was an O/O & was on percentage pay & it was in the trainer's contract that he would not get d/h pay.

Answer:
As already said. Most companies that pay by the mile will pay for all dispatched miles, both loaded and empty (though occasionally the pay is different). Companies that pay percentage usually do not pay for deadhead miles though in the end it often equals out as the pay for loaded miles is often higher.
As to how far a driver may deadhead to pick up a load. This can be anywhere from across the street to across the country. (I have talked to drivers who have deadheaded or bobtailed over 2000 miles to get a load).
The only problems I have ever run into with getting paid for deadhead miles (and I have always worked on a cent per mile basis) is when I go for one load and get there and that load has been cancelled and then get dispatched on another load. Sometimes dispatchers will screw up and not add in the first deadhead miles to the empty miles for the new trip. That is why it is important to always keep track of your trips and the miles they pay.
Answer:
I just deadheaded from Seminole, Texas Tp Lincoln, Ne so I could pick up a ;oad in Omaha Monday. Got paid full rate for evey mile I drove.

Answer:
One time when I drove OTR for a carrier that shall remain nameless, so, I'll use the initials in an attempt to conceal their identity, CRE, they deadheaded me, one time, in the dead of winter, from Pittsburgh to Oregon....just to get me out the house on my time off, as they had no other loads that needed to be covered in the area.! Needless to say, I refused it, but, they still would have paid me.