The cogs of retail agree: a Gears of War 2: Game of the Year Edition will soon emerge. The package will allegedly bundle the full game with the $20 All Fronts retail compilation which includes the Flashback, Combustible, Dark Corners and Snowblind map packs along with the deleted "Road to Ruins" campaign chapter.
GameStop currently has the product listed at $40 while Amazon has it for $37; what they both agree on is that the GOTY edition has a September 1, 2009 release date. We're currently confirming the release date, price, and existence (!) of the GOTY edition with Microsoft and will update as soon as we hear back on our coms.
Update: Microsoft has confirmed the bundle will release September 1 for $40 in the US.