The big trouble with lingerie shape wear is that it doesn't work well enough in fit, or breathe adequately in hot weather. Just when you want a bit of coverage beneath a summer dress, it gets sweaty and twists around, up and is generally a mess to untangle or smooth down.
If I'm wearing a denim, chambray or dark dress, I pull on a pair of Nike Pro bike shorts (wicking, with a non-roll waistband although lurid colors) or one of Stella McCartney's bike shorts made for tennis (more femme colors than Nike, including a decent peach nude). For an expensive option, try Free People Victorian bike shorts, they're lacy-femme and ultra comfortable, but hard to find. With all of these options, I'm decently covered for sitting down, no thigh rub or roll-ups, and the waistband is flat and doesn't show. The Nike Pro shorts aren't sexy by any standards (yet they work really well) but the Stella and Free People bike shorts are fun, flirty and very comfortable.
I think someone could come up with a wicking, smooth bike short in cute colors and solve a huge summer problem!