If you're looking for a modest long prom dress with lots of sparkle, here's one that is sure to shine. With rows and rows of sequins on the sheer long sleeves, this long a-line formal dress from Amelia Couture is an eye-catching choice for prom, military balls, and other black-tie events. A sweetheart lining peeks through the sheer sequin bodice of this long sleeve evening gown, while sequin bands at the waist top the floor-length long a-line skirt. In misses and some plus sizes, this modest long sleeve long prom dress is surprisingly affordable, at under $200.