orange chocolate ale

....I know I know, this sounds a tad bit "fruity" (oranges aside), but here's what I'm thinking: an middle weight american brown, moderately bittered and late-hopped with the most citrus/mango american hops available (Cascade/Amarillo), a bit of orange zest at the end of the boil and, as Jamil does it, a decent rest on top of some cocoa powder sludge in primary.....

does this sound good only in theory, or might I end up with a beer to wow my wife and the neighbors without surrendering my thirst for well-hopped brown ales?

Here's what I'm thinking:
8.00 lb Pale Malt, Maris Otter (3.0 SRM) Grain 76.2 %
1.00 lb Victory Malt (25.0 SRM) Grain 9.5 %
0.75 lb Caramel/Crystal Malt - 60L (60.0 SRM) Grain 7.1 %
0.50 lb Chocolate Malt (450.0 SRM) Grain 4.8 %
0.25 lb Caramel/Crystal Malt -120L (120.0 SRM) Grain 2.4 %
0.50 oz Cascade [5.50%] (60 min) Hops 9.7 IBU
0.50 oz Amarillo Gold [8.50%] (15 min) Hops 7.4 IBU
0.50 oz Cascade [5.50%] (20 min) Hops 5.9 IBU
0.50 oz Amarillo Gold [8.50%] (5 min) Hops 3.0 IBU
0.50 oz Cascade [5.50%] (5 min) Hops 1.9 IBU

Est Original Gravity: 1.054 SG
Est Final Gravity: 1.014 SG
Estimated Alcohol by Vol: 5.2 %
Bitterness: 27.9 IBU

also, what yeast? S-05, S-04? american or english?

This sounds pretty good to me. I've seen it somewhere else on the forum though. Someone did a orange chocolate beer as a christmas gift, but I can't remember who.

I'd go with American yeast because it's a more neutral yeast IMO.