The feedback was loud and clear - a shawl collar will be faster than a notched collar, so that's what I'll do. Thanks so much for the advice! I found several options in BWOF:
6-2007-107 I totally dig the two layers at the collar and cuffs - great potential for using contrast fabrics there. But it has a drawstring at the back waist instead of darts; I could add darts, but let's see what other options we have...
12-2007-115 I loved with this when Kristy made it in a classy charcoal wool, and then she made a second version to accommodate her baby bump! This was a close 2nd place for me, but ultimately I chose:
9-2008-129 This is the jacket Dawn was thinking of. I think it'll look good worn unbuttoned. I'm going to round out the corners at the hem. I may omit the folded up cuffs.
I've got my fabrics all lined up too! Yesterday I ran out and bought a cut of black satin to use on the upper collar for a "tuxedo" effect. From the stash, I'm using a woven black rayon as the fashion fabric, and I'm still deciding on the lining - either a Burberry stripe, or a dark pink (alleged) silk that a friend got in Thailand a while back. The satin is rayon/acetate and the bolt said "dry clean only", so I'll treat this as a dry-clean garment and proceed to cutting out the fabrics without pre-treating - yippee!