A full training material, I dont know of one. There are some decent books have it as a topic. I would definitely try and get a hold of Boeings Jet Transport Performance Methods as it has a very good section on obstacle clearance max weights.
If you fly Boeing equipment, you should be able to get a copy from your carrier's Airline Support Engineer.
I have the Airbus Getting to Grips with Aircraft Performance, and it doesnt have nearly the info vs the Boeing JTPM.