This mech paper model is Flea, a mech from the video game MechWarrior 4, the papercraft is created by BLaaR. The size of finished model is about 155 (H) x 112 (W) x 101 (D) mm. There is also a MechCommander 2 - Simple Flea (Fire Ant) Paper Model on the site.
You can download the papercraft model here: MechWarrior 4 - Flea Free Mech Paper Model Download [Skins]