"It's whats inside that counts...my friend...it's not the jacket it's the tailoring" - The Mighty Boosh

These images are of my initial attempts at the vest and sleeves.
The overall shape I am happy with although the size and shape of the armhole needs to be tightened to continue with the streamlined look. The back of the shoulder piece will become less heavily and more yoke-like to compliment the vest structure if worn underneath. So far I like the success of the pieces as individuals and worn together with either as the exterior.
I think this is also a good starting place to draw the collar and lapel piece to compliment these structures.

The function is definitely influencing the design process at this stage...