I've finished building an MSV Full Armor Gundam based on the Katoki Gundam. I wanted the MG Full Armor Gundam but didn't think I could afford it, so I got frustrated and decided to try building one using the Katoki Gundam I already owned as a base. The shoulder cannons and the weapon on the right hand were easy to attach thanks to the Builders Parts that fit nicely, but I had a bit of trouble finding a good small shield for its distinctive shape. In the end, I used some mysterious leftover parts from the Unicorn Gundam to make it look somewhat similar.

Katoki Gundam Base MSV Full Armor Gundam | GT400's Gunpla works