I'm pretty sure that the odds on Megabucks are the same everywhere. It is a "proprietary game," meaning the casino and slot maker (IGT) share in the profits. As I understand it, such propriety games are generally set to a return of about 88% by the slot maker, and the casinos do not have the option for a looser or tighter version.
The Wheel of Fortune game, with the big jackpot, I believe is also a proprietary game.
Video poker odds are dictated by the pay table. For example, a 9-6 Jacks or Better game will pay 99.54%, assuming optimal strategy and an infinite amount of play, regardless of where the machine is or number of number of hands the player gets on the draw.