Remember... a chastity device, per se, isn't merely denying you an orgasm. It denies you the ability to use your cock. (Just as it denies a woman from using her vagina by blocking the entrance. In fact, on a woman, it doesn't actually have to be deny an orgasm and many leave the clit available (especially for teasing.)

So... in order to have a make chastity device that will allow a hard on, it would have to be encased in a device large enough to deny you entrance into an orifice.

That might be so weighty or bulky as to be unwearable with clothing.