The last time I heard anything, yes the "secret menu" at ASMo is still available with the briefcase and all. Other secret menu items include:
Cosmic Ray's Starlight Cafe --- Galaxy Loaded Fries --- Use Disney’s mobile ordering system to get these fancy fries. These are loaded fries topped with bacon, pico relish, garlic ranch sauce. cheese sauce and flaming hot cheese dust.
Whispering Canyon ---- 10 Gallon Challenge Sundae --- This treat contains: one scoop of vanilla, chocolate, strawberry, and mint chocolate chip ice cream, PLUS a whole slice of apple pie, a vanilla cupcake, a chocolate cupcake, chocolate brownie, 2 Mickey sugar cookies, banana, pineapples, cherries, Oreos, strawberry sauce, caramel sauce, whipped cream, toasted marshmallows, and pieces of chocolate covered bacon to top it off!
Pecos Bill Tall Tale Inn and Cafe --- Nachos Rio Grande --- only served between 3:00 - 6:00 p.m. (but I think this one might be retired)
Kona Cafe --- 'Ohana Bread Pudding --- It’s not listed on the menu but if you ask you will receive!
D-Luxe Burger --- BLT, Donut Nuggets, Bacon-and-Blue Burger, Onion Rings and Grilled Cheese --- Can only be ordered through the Mobile Ordering of the MyDisneyExperience app