I am in the middle of putting up a Miracle Truss building. Actually just got done with having the foundation poured and the concrete folks messed up the location of one of the bolt sets for one of the truss's.
Not sure yet how I am going to deal with that.
The building I ordered was one with 8ft walls, it actually came in at 6ft 8in. Seems they measure the wall height on the outside of the wall from the ground to the roof top, at the wall. In which case mine is 8ft, but the INSIDE clearance height is only 6ft 8in due to the truss frame.
Since I am putting the building on a 3ft stem wall, that is not a major issue for me. If I was putting it on a slab... it would have been a major clearance issue. Be VERY careful of exactly what dimensions you are talking about with these folks.