I saw your idea a couple days ago and started looking for a metal ammo box. Wal Mart site says they are out of stock, but I knew I saw some there maybe 2 months ago. Sure enough they had 3. Got one today.
Also, Harbor Freight site says they have them.
My smoker has a 3 by 4 opening. I thinking I will set it up and prop the door open. I'd rather wait before I take the chip door off. It may work fine with it on.
Any thoughts or ideas that you've had since last April? Is the seal still okay? I figure it might be able to be taken out and use some lava lock if needed.
Anyhow, I'm glad you shared this.