I don't, unfortunately. It would essentially resemble a baseball cap, and my idea was that it would consist of one layer of Oreo cookies, stuck together somehow. That's where the royal icing would come in.
Ah ok. I guess it would be possible, but I think it would be messy and difficult due to the fact that Oreos are round so there will be gaps between them. Are you planning on doing a trial run? If royal icing isn't strong enough then you could always try a gum paste glue.
You can use Royal Icing as "glue", but your problems here would be stability and wearability.
Like Becky said, Oreos are round and can only be put together a certain way.
The problems I see with this is that Oreos are not stable enough to handle being "glued" together and being able to be held without breaking the cookie part. I also know from experience, unless you are EXCELLENT at making the right consistency of Royal Icing to hold something like this together, it just wont hold it.
You can try, but I will be shocked and amazed if you pull this off! And if you do, I definitely want to see pics!!!
I've used royal icing as glue in the past, but only with straight edges. I'm with Becky and Chester on this. Is there something else besides Oreos that you would consider using? I've never used gum paste glue, so I can't speak to whether that would work, but since it has glue in the name, perhaps it would be a better choice for your project.