I did this one several months back, it's not actually completely finished, in that the skirt is still to be dealt with, but I have worn it as a bra and belt set with a hipscarf.
This started life as a cheap wedding dress from ebay, it was too big for its original intended use, so I decided to butcher it for a white costume.
So here are my raw materials, a dress and a solid Egyptian bra base. These are available from costume vendors like Everything Egyptian. I got this as a job lot from and Egyptian costumer.
I unpicked the bodice from the dress
Then I sewed it onto the bra base
The dress didn't completely cover the soup-bowl cups, so I added some large hotfix rhinestones, and filled in the gaps with smaller ones
Intermediate shot, the straps were extended with webbing (for a cross back) and covered in white satin ribbon.
The belt part was made by taking a section from the top of the skirt, and using it to cover some wide elastic. The oval at the front is cut from a plastic container and covered in white fabric and hotfix. The large crystals on the front came from a buckle. I also added some crystal buckles to the front of the straps. The back is fastened with the old cross straps and rings method I used here
Dodgy selfie. The silver fringe is a separate piece.
Action shot from this video
I plan to finish the skirt at some point, I still have enough of the dress left to make a column skirt, with one or two slits. I just need to add a waistband and hem the edges of the slits, which will probably happen 2 days before I have the occasion to wear it.