You'll get a much darker beer if you use amber LME. You could still certainly use the regular hop schedule and come out with a "Centennial Amber" instead of a blond. But I think it's going to be a redder and more caramelly beer than the clear & crisp taste of the original.
However I did a little searching and found this suggestion "You could steep 4 oz of chocolate malt, then add 6 lbs of the amber LME, and ~22-23 IBUs worth of Fuggles hops to make a nice Northern English Brown." from this thread: http://www.homebrewtalk.com/f37/8-lb...ed-use-350529/
And here's an "Imperial Amber Ale" with honey that looks interesting... like a stronger (and differently hopped) version of the White House Honey Ale, maybe. Weird. http://www.homebrewtalk.com/f63/simp...er-ale-334047/