Have either the skirt of the dress or an under-skirt be a hobble skirt? Possibly cuff/tie the knees or ankles together for a similar effect?

Wear very high-heeled shoes, and have them locked on? With a long enough skirt it wouldn't be noticable.

If the dress is designed *just* the right way, you might be able to have a posture collar under it. Or something attached to the back of the gown that goes into the hair or to a tiara or coronet for a similar effect. Could be hidden if your hair is worn down.

I second the idea of the corset, but then I'm a corset junkie. ;-)

Crotchless/no underwear with a garterbelt? Certainly could be interesting when it's time to throw the garter.

Not allowed to turn down anyone who asks for a dance, but get a set number of stripes on the ass for each one?

Some form of decorative collar would probably not be too hard to manage.

Nipple rings? A navel piercing with her honey's initials or insignia on it? Those can take a while to heal.

Or the ultimate in torture... the bride is forced to dance the chicken dance and/or the Macarena. :-)