RGM-79Pt

The RGM-79Pt, or GM Strength Type, was designed as a heavily-armored GM variant that sacrificed as little mobility as possible. Unlike most GMs, its design was primarily based on the RX-78-1 Prototype Gundam instead of the RX-78-2 later version. It features larger and more powerful thrusters than the basic GM and a second beam saber, as well as thicker, more resilient armor. It was produced in limited quantities, but the difference between this unit and the standard GM were not as well-defined as originally thought. Because the changes in the design were not as dramatic as originally expected, many pilots were said to have preferred the original GM, and the design was deemed too expensive for continued production.

Originals available at [link] -- used as publicly-released material.