Some of the mecha in Gundam do have a bit of a medieval armor look to them at times-the Gyan of course is the most obvious example (as well as similar suits in Z/ZZ), although the Gouf as well, especially since it seems designed more for melee combat than it's Zaku cousins.
The Gundam itself is patterned after Samurai armor, and the Marasai and Sazabi also seem to have major Samurai influence in their designs, in particular their helmets.