Here is the pattern that I finally settled on to make my LBD:

My dress is laid out on my cutting board, waiting for the final steps. The side seams have been carefully pinned together, to be hand-basted for a final fitting. Then, I will machine stitch the hand-basted seams (after any necessary adjustments), leaving room for a side zipper. Still haven't decided if I will use a lapped zipper, to be sewn in by hand, or an invisible zipper, to be sewn in by machine. Finally, the lining will be handstitched to the fashion fabric at the armholes, neckholes and zipper tape.
Tonight was taken up with preparing for Jennifer Stern's machine embroidery class at Patternreview. I've known Jennifer for years, in fact I bought my Janome sewing machine and embroidery machine with her help. She does incredible embroidery on upscale clothing, and I am eager to combine her techniques with my LBD. For summer, I see this dress in a handkerchief linen (underlined, again, in silk organza, and underlined perhaps in a habotai), with subtle tone-on-tone embroidery, perhaps winding up one side.