Oh that dress is so pretty!!
That's the style of dress I am getting made, I have a sash too and I've kept it as a plain ribbon because I have pearl buttons all the way down the back of my dress.
THe dress maker is making a 'belt' that clips into the ready tied bow. This will ensure it will last through the day and I won't have to re-tie it.
There are some amazing beaded sashes though. You can even go to a fabric shop and get a cut of beaded lace and sew it to a sash??
Or search ETSY!
If my dress didn't have all the detail at the back I would have had a bling bling sash made