Fleshwarper's do indeed become aberrations as a capstone. Their prestige class requires Heal 10, knowledge (Arcana) 4, graft flesh and a familiar to qualify. (You technically don't even have to be a spell caster to get in). they have 9/10 casting and graft reserve points akin to artificers and get special qualities as they go up in levels to make them more akin to aberrations.