I basically took the half-machine template from dungeon magazine and tweaked it a bit. Please note this template is FAR FROM FINISHED but if anyone wants to add something to it before me then please feel free too. I'll try and keep up on this as best I can (my work schedule is so tight right now I feel like I'm begin hung by a tree limb).
Special Attacks: A half-robot gains one half-robot special attack from the list below for every 3 points of CR (minimum 1—the first ability chosen must always be arm mount).
Arm Mount (Ex): The half-robot has had one of it's arms replaced with an apparatus capable of mounting a early or advanced firearm (this includes the advanced firearms listed below).
Biochemical Grenade (Ex): The half-robot can fire a grenade loaded with an artificially created biological poison. The half-robot must possess the Grenade extraordinary ability to select this special attack.
Breath Weapon (Ex): A half-robot can belch forth a gas-based breath weapon that either mimics the effects of the sleep spell or the slow spell (choose one when applying this template; the choice cannot be changed later on) as a standard action once per day.
Chain Gun (Ex): The half-robot has a chain gun attached to one of it's arm mounts.
Electrocute (Ex): The half-robot can cover it's body with a powerful electrostatic field as a standard action once per day.
Freeze Ray (Ex): The half-robot has a freeze ray attached to one of it's arm mounts.
Flamethrower (Ex): The half-robot has a flamethrower attached to one of it's arm mounts.
Extra Limbs (Ex): The half-robot has an pair of limbs.
Grease Spray (Ex): As a standard action, the half-robot may spray cone of oil and grease.
Grenades (Ex): The half-robot has a grenade launcher attached to one of it's arm mounts.
Mechanical Tail (Ex): The half-robot has a scorpion-like metallic tail attached to it's back.
Metallic Claws (Ex): The half-robot has had the hands of two of it's limbs replaced with metallic claws.
Metallic Jaws (Ex): The half-robot has had it's teeth replaced with metallic jaws.
Special Qualities (Ex): A half-robot gains one half-robot special quality from the list below for every 3 points of CR (minimum 1—the first ability chosen must always be metallic body).
Metallic Body (Ex): The unusual construction of the half-robot leaves them gives them certain advantages as well as certain vulnerabilities that normally do not apply to living creatures. The half-robot gains a +2 racial bonus to it's natural armor (or has it's current natural armor improved by +2). Furthermore, due to the structural reinforcement of it's body, the half-robot ignores critical hits and sneak attacks 25% of the time. Finally, due to the half-organic/half-mechanical nature of the half-robot, spells and channeled energy that restore hit points only restore half the usual amount (minimum of 1). However, the half-robot can benefit from the mending and make whole spells (though the later only has half the normal effect).
Ability Boost (Ex): Cybernetic technology allows the half-robot to enhance or replace muscles and organs , enhancing its innate physical abilities.
Climbing Claws (Ex): The half-robot's claws are specifically designed for climbing in mind. The half-robot must possess the Metallic Claws extraordinary ability to select this special quality.
Damage Reduction (Ex): The half-robot gains damage reduction based on its Hit Dice.
Enhanced Scent (Ex): The half-robot gains the Scent ability.
Flight (Ex): The half-robot gains rocket jets on specific parts of it's body which give it the ability to fly for a number of rounds equal to it's hit dice. This ability may be only used once per day.
Forcefield (Ex): The half-robot is equipped with a generator that enables it to wrap itself in a protective forcefield for a number of rounds equal to its Hit Dice. The forcefield absorbs a total amount of damage equal to 10 points of damage per hit dice of the half-machine. If the forcefield goes beyond this theshold of damage reaches the end of it's duration, it immediately dissipates. This ability may be only used once per day.
Haste (Ex): The half-robot can activate special adrenaline injectors, essentially granting the half-machine the effects of a haste spell for a number of rounds equal to its Hit Dice. This ability may be only used once per day.
Cloaking Field (Ex): The half-machine is equipped with high-tech stealth technology which gives the half-machine the ability to duplicate the effects of an improved invisibility spell for a number of rounds equal to it's hit dice. This ability may be only used once per day.
Leg Servos (Ex): The half-robot's legs are equipped with powerful leg servos.
Nano-Regeneration (Ex): The half-robot carries a package of nanites which it can release into it's circulatory system to repair itself of damage.
Optic Sensors (Ex): The half-robot has had it's eyes replaced with advanced optic sensors.
Rust Protection (Ex): The half-robot gains immunity to rusting attacks.
Telescopic Limbs (Ex): The half-robot is able to extend two of it's limbs thus increasing it's reach with those specific limbs by 5 feet.
Abilities: A half-robot’s Strength, Dexterity, and Constitution scores increase by +2 however it's Charisma score decreases by -4.
Challenge Rating: Same as base creature +3.