I'm pretty sure there are a couple of companies that make adr approved cf bonnets. I can't remember if its all carbon or fibeglass with a layer of carbon over the top. A cop would still get ya for it though.
Edit: Had a look at this thread and it be something you'd need to get engineered rather than relying on adr approved products.
In the end they'll give you a defect for what they like so it's more a question of if it will pass regency.