I've never seen what you're describing, but the description that's been used throughout this thread has been exactly what you mentioned they don't have to be.
The ones I have on are Duluth Trading....and after some looking i can't find such a thing on their website haha. Nylon yes, stretch no.
Bottom line: being a dude who's insecure about their clothing is infinitely less attractive than rocking cargo shorts with no shame.
