Googling "gottlieb playfield" led me to this: http://www.mondialgroup.com/gottlieb.htm
Ron and Nancy Webb and Shay do GREAT work, but I don't think they do playfields. That just leaves CPR and Great Pinball. EMs are typically low-dollar games, but I recently heard of a C37 playfield going for well over $1000. So the demand is there for top titles. Clearcoat would NOT be needed; I assume most of us EM collectors would want to wax and roll.
If you have an EM that you'd pay over $500 to buy a new playfield for, please link it above.