I made my own stencil for a damask cake I did a few weeks back. I got a plain stencil sheet from Hobby Lobby to it. It took a while to cut out all the little pieces and designs but the results were as good as any.
That's a really pretty damask pattern. I'm doing one at the end of this month. It's a Martha Stewart cake. I was having trouble finding the exact pattern, so I emailed Martha's crew. They told me to buy the book, copy the picture, and enlarge it for my needs. So what I ended up doing was figuring out a good size, and then I taped them to a board with wax paper over it. And I'm going to use RI to fill in the pattern. (Which is exactly what they told me to do). Now the cake that she picked was RI anyway. The one you have looks like fondant. But you could still use the technique to cut those out, although it would be hard. See if the bride will let you do RI. I was just practicing mine, but I think it's going to work really well. Good luck!