How would you make something like this? The flaps need to be opened. I haven't a clue how to start and not making the flaps just fall completely off.
Are you planning for them to be opened and falling to the outside or just open and standing straight up?
You could make them out of either gumpaste or a gumpaste/fondant mixture and let it set up for days before you needed it. I think either way they would be VERY fragile (not to mention if they are to fall open, you've got the "L" shape to deal with while drying) and depending on how/where it's delivered it could be tricky.
I might be inclined to use foamboard and cover it with fondant. At least you would then have some strength to it and thickness. Obviously, they would not be edible.............. I'd like to see a picture of it when you are done.
Well I didn't hear back from her so maybe she found someone else. :) I was kinda looking forward to it!