The really upscale restaurants at Epcot (Bistro de Paris) or in the Epcot resort area (bluezoo, Yachtsman Steakhouse, Shula's, Flying Fish, Il Mulino) don't do lunch. Your best bet for an somewhat upscale lunch is probably Chefs de France. Had lunch there last week and it was wonderful.
DH & I have had lunch twice at Le Cellier - great food & attentive service; also really enjoyed Chefs de France (smaller, more intimate atomosphere but I think I liked Le Cellier's menu better).