Would require Robotics Expert 1 and Local Leader 2 to build and each option would require subsequent Perks ie. Robotics Expert 2 and Armorer 1 or Science 3 etc.
Upgrades would be as follows.
Standard Chasse
Improved Chasse
Advanced Chasse
Thrusters
Fusion Thrusters
Flame Thrower
Laser
Plasma Blaster
Plasma Caster
Buzz Saw
Ripper
Super Sledge
Would also include several paint jobs such as Butler for Codsworth and Nurse for Curie.
Edit: The first option would be the Factory Standard. Essentially repairing the rusted or destroyed preexisting parts.