BB Dakota Sleeveless Black Dress from Gwynnie Bee has low deep arm openings. I found the only solution was to wear a jacket. If it was spring that okay but when temperatures are in the high 90s, you won't want to spend much time, outside.
P.S. With A/C usually running high in public buildings the jacket is a must!
If you're interesting in giving Gwynnie Bee fashion subscription a try, they're still offering a month free trial!