Hey, I was looking into brewing the 10 gallon version, but I was doing a little research on Great Lake's site and noticed that they post PDFs of generally what goes into their brews. Obviously it's not a clear-cut recipe, but it might help make a better clone...
Here's the link to the Christmas Ale PDF:
http://www.greatlakesbrewing.com/uploads/Beer/GL09-709 TastingGuideLong_5 7 10 (3) 23.pdf
For simplicity, I'll just copy and past the important info:
MALT
Harrington 2-Row Base Malt: Allows color and flavor from other specialty malts to come through; makes for very clean beer
Wheat: Adds body and head retention
Crystal 45: Contributes to copper color and adds sweet caramel aroma and flavor
Special Roast: Contributes subtle hints of toasty and biscuit flavors
Roasted Barley: Added in small amounts to contribute to overall complexity and color without overwhelming
SPICES
Honey: An adjunct to add strength and fresh floral notes
Cinnamon: Imparts festive aroma and flavor
Fresh Ginger: Adds spicy aroma and flavor
HOPS
Hallertau: U.S. version of classic German noble hop; contributes mild bitterness and fine aromas
Cascade: Used as an aroma hop; citrusy aroma complements beers heavy spices
So yeah, any thoughts? I'm tempted to come up with a recipe from scratch, or adapt the previous recipe to match the malts better... but I don't have much all grain brewing experience (only 1 pretty good stout) under my belt, and I'm not sure how it would end up. We'll see though, maybe I'll risk some experimentation...