This is a timely question, in light of the recent firing by Wynn Resorts of two-time James Beard Award-winner Paul Bartolotta, with an unusually candid press release from the property stating that "It has been a staple of the Wynn culinary philosophy that the chef whose name is on the menu is the person who actually prepares your meal." Ouch! (The renowned seafood chef is not on the Food Network roster, but has had plenty of television airtime, including appearances on Bravo's "Top Chef" and on "Iron Chef America.")
Bartolotta's absenteeism is the norm rather than the exception, however, when it comes to "big name" restaurants in Las Vegas and the owners of those names; you'll be lucky to catch any of your favorites from Food Network in the flesh. Here's an overview:
Reading about how the presence of the TV celebrity can prove overly disruptive to restaurant operations was an eye-opener that made a little more sense to us of why many of them are seldom, if ever, to be seen again on property, once the fanfare and media feeding frenzy of opening night has run its course. Still, the cynic in us is pretty confident that this is only a small part of the answer -- after all, if the "Name" was hard at work in the kitchen (assuming it wasn't one of those open affairs, à la Giada), then the only indication diners might have of their proximity to a culinary deity would be via that certain je ne sais quoi experienced by their taste buds.
As far as some other celebrity chefs of TV fame are concerned, Hubert Keller recently co-hosted the Chalk Hill Wine Dinner at Mandalay Bay, with Director of Wine, Harley Carbery and Vice President of Vineyard Operation at Chalk Hill Winery, Mark Lingenfelder, which included a four-course dinner at Keller's Fleur restaurant at Mandalay Bay (it was $110/person, plus tax/gratuity).
Gordon Ramsay made a surprise visit to his Burgr restaurant at Caesars last October, we learned via a post to celebrity-sighting site Smarp.com. Ramsay was also spotted, in May of last year ,partying at MGM Grand's Hakkasan nightclub with "Cake Boss" star and Venetian/Palazzo restaurateur Buddy Valastro. The duo were both in town for the annual Vegas Uncork’d food-and-drink festival by Bon Appétit, which features lots of the type of interactive-cooking demos that you reference. We haven't heard anything about the specific sessions you ask about, although every now and then something of this nature does occur, like the recent event hosted by Sinatra at Wynn. Bellagio also has its custom-built Tuscany Show Kitchen, which stages special interactive cooking classes and demos, sometimes for invited guests only, on other occasions open to all, for a fee. The Executive Chef’s Culinary Classroom events, scheduled to take place on Aug. 27 and Sept. 29, however, were recently canceled with no explanation given.
Returning to the Vegas Uncork'd concept, in this may lie the key to spotting a famous chef around these parts, especially one in action: Don't expect to catch them with their sleeves rolled up, back-of-house at their own restaurant, but instead target this and the other numerous food festivals that punctuate the Las Vegas event calendar, like Vegas Food & Wine, the Food & Wine All-Star Weekend, or Las Vegas Epicurean Affair, when you'll find the city, in particular the host venue(s), awash with famous chefs who are often sharing/showing off their skills and signature-dish preparations.