I can unlock the servo body and head (which the game classifies as "hair") the problem with that is the sims face will still be there like a mask over top of the servo head and I don't know how to get around that. Well I know a way but it involves editing the character's file manually in SimPE and is something most people probably won't feel comfortable messing with.
The way around this is to use the headless (faceless) genetics that are floating around out there. I forget who it's by, but I believe it's available on ModTheSims2.com,. I'd double-check, but the site is unreachable for me at the moment.
I think they're under costume makeup and unlocked anyways. They're not part of the work outfit. I think Tybalt wears the "Criminal Mastermind" one, and the supposed Captain Hero one is blue.
Thanks for pointing those out. I don't know how I overlooked them.