There are so many talented restoration ppl... I would start off with Phet but quickly add
Nash (for 720) - Could be with anything Atari but I've seen what level of restoration he goes to before allowing a game to enter his realm.
Van (for most Nintendo resto) - She goes above the norm, making sure to use exact hardware, down to the same f'n bolts/nuts. The exterior finish process she's been able to create on her Punch out and other Nintendo cabinets is something to seriously give props to. She doesn't discriminate either...there are non-Ninty projects she gives equal love to.
pr0k - The Screw Loose project still takes the lead. Not only restoring but building a game that had never been produced. Impressive. I think he also worked on a (non-meth) Sundance that had a soggy bottom.
It goes well beyond just buying repro artwork, stripping sides, painting cabs and parts. I think those that restore w/ complete accuracy, or even creative additions should be recognized. Of course, those 'creative additions' should in no way include a T-n-F cabinet with shoes on it, or a Pachinko with Star Wars stickers. That's not restoration, that re-destroying.
Phet's Lost Tomb(er) was a great example of improving an existing design.
Van is currently working on a few projects that are custom but great improvements of existing games. Perhaps she's posted progress or will soon.