Read on for the sketch progression images.
Initial rough sketch, scanned into Photoshop:
Initial rough cleanup sketch, created in Photoshop CS4 with a Wacom Intuos4 graphics tablet:
Working final line art. Although not complete, I used this to go to the rough color stage to experiment:
Working color art test:
Chest emblem added & background cape darkened to make the foreground blues stand out a bit more: