<a href="http://www.eoghann.com/2014/06/marvel-comics-fan-art-captain-america/captain_america_d_day_by_loganx0-d7n5ovq" rel="attachment wp-att-119549">Here's a great bit of work by LoganX0. Not only has he drawn an imposing Captain America (I like it when the chainmail/scalemail actually looks like metal armor) but he's also tapped into the early years of the character by using the beaches of Normandy and the D-Day landings as the setting for the image.
Sticking to the grey palette here was a good call I think. It adds a somber note to the whole image. The choice to angle the composition is an interesting one too. It gives the whole thing an off-kilter feel.