One thing you can do if you can't find a suitable bun is buy a panini, sub or hoagie bun from the supermarket ad heat it up for a few minutes in the toaster oven..This will harden the crust..let it cool and try that..
The Safeway ones are 8 ounces and long enough for at least two sandwiches. When fresh they have a pretty good crust on them, but still soft on the inside. If you want it even crustier just leave it on your counter for a day or two and they'll get really crusty!I will have to try Safeway. A sandwich size baguette would be great