G'Day Adam.
Sorry mate, just found this thread or I could have helped you a great deal earlier.
It seems you have discovered that your original nay-sayer was a little over enthusiastic.
Juddy and I used the same mobile Roadworthy service and found them to be great. Happily refer anyone in Brisbane to them. PM for details.
The most common experience has been that DoT simply confirm the chassis/ VIN/ engine numbers and seating capacity as per compliance plate.
Rule of thumb: stay away from the larger inspection stations, less chance of striking someone who know too little or has too much time available to cause you trouble.
Phoenix, perhaps we could create a register of inspection stations who are familiar with the vehicles to help new owners? Add a caveat emptor notice and it should be Kosher.