This mech paper model is Warhammer IIC, a mech from the game Classic BattleTech, the papercraft is created by Whammy. The size of finished model is about 288 (H) x 271 (W) x 193 (D) mm. There is also a Warhammer Mech Paper Model on the site.
The original Warhammer was designed as an assault BattleMech. However, it had been superceded by later and heavier 'Mech designs, though it remained a powerful weapons platform. The Clans wisely maintained and built on this solid frame a real assault 'Mech, the Warhammer IIC. Thanks to their technological expertise, they were able to add ten tons with the same speed and firepower and nearly double the armor of the original. The Warhammer IIC is built on an Endo Steel frame and is protected by twelve tons of Ferro-Fibrous armor. The result is a dangerous 'Mech, able to hold its own in any battle against the Inner Sphere. Also note that the armor was the primary concern when designing the IIc version rivaling even 100 ton assault mechs in durability and protection. [Source: sarna]
You can download the papercraft model here: Classic BattleTech - Warhammer IIC Free Mech Paper Model Download