GameStop has since removed their Gears of War Ultimate listing, but Microsoft did confirm the mysterious bundle's existence. In case you had something better to do than compulsively look up "Gears of War" on the GameStop site and missed out, we're referring to the $29.99 bundle that was listed for a short time, with a February 15 release date.
Yeah, it's gone now, which is completely understandable. Still, we know it's real! Microsoft did note that the name was subject to change and it doesn't pertain to Gears of War 3. Here's the official word:
"We can confirm a forthcoming bundle SKU involving the Gears franchise, though this may not be the final SKU name. There are no specifics available at this time, except to say it will not involve Gears of War 3 or the beta."
If you're looking for an early taste of Gears 3, access to the public beta is available by simply pre-ordering Bulletstorm Epic Edition.