According to the Rogue website, they consider Dead Guy as a "Maibock fermented with an ale (pacman) yeast." From their website: Dead Guy is a German-style Maibock made with Rogue's proprietary "PacMan" ale yeast. It is deep honey in color with a malty aroma, rich hearty flavor and a well balanced finish. Dead Guy is created from Northwest Harrington, Klages, Maier Munich and Carastan malts, along with Perle and Saaz Hops. Dead Guy Ale is available in 22-ounce bottles, 12-ounce 6-pack, and on draft.
Measurements: 16 degrees Plato, IBU 40, Apparent Attenuation 78, Lovibond 16
It's fermented at 60 degrees and not lagered, so it's not a Maibock. I think it's generally undefinable.
As far as AB, I would consider that an American strong ale. It's one of my favorites, as is the Dead Guy.