I would say that an option for a prosthetic limb (directly competing with basic cybernetics) would be a necrograft, that literally gives you a Phantom-Limb, a Ghost arm. and just like at higher levels you could (probably) augment the cybernetic limb, you might be able to enhance the ability of the Necrograft, letting it phase through matter, actually become invisible. give you a special unarmed attack, etc.