Basically, I have an Android who wants to go about that whole Pinnochio story, but in reverse. He wants to embrace his artificial side and build himself up as a construct. Is there any way to modify himself physically to do this? IE, robotics instead of skin, mechanized body parts, etc. He just wants to shed his skin, quite literally, so become a robot.
Yes, using the technology guide
Androids are native from Numeria, where a spaceship has landed into Golarion and bought lots of alien technology to that region. There is an official campaign set in Numeria: Iron Gods. That said, the Technology Guide Campaign Setting book expands on the flavor and rules from that hightech part of the setting and rules and introduces dozens of new technological equiipment, including Cybertech.
Those are implants that replace your organs and/or limbs by technological replacements, from drone eyes, to metal-hardened skin, to full arm and legs replacements. Those items are expensive and balanced just like magic items, using up slots on the character's body. So, instead of a pair of magical boots, the character could replace his legs with a cyber replacement.
Take a look on those rules, they will fit on his idea just perfectly.