I got something like this http://www.amazon.com/Nordic-Ware-Classic-Metal-Covered/dp/B0006SGQFY
I haven't used it a ton but I like the idea. I also got a pack of I 30 disposable cake pans for $6 at Costco, $0.20 each. I do use them multiple times until they are pretty nasty and all the drippings have turned to carbon three or four times.
Ah, so at a little over 15"x9" it should fit in the middle of a 22, with coals to either side? That's useful, you toss in your disposable and cook in it, with or without meat drip, and have a way to remove it without the disposable folding up.
Or maybe you'd use it differently.
I actually hadn't thought about using the disposable inside of the reusable one, that's a really good idea. I actually bought the reusable pan and forgot about it, then picked up the disposable ones. The thought was to replace disposable pans with the reusable one - it's about the same size, can serve as a drip pan between coals or even on one side of a direct/indirect set up, hold food, or really anything else. It's dishwasher safe. I'll probably beat the crap out of it until I only want to use it as a drip pan and see where it goes from there.
I'm kind of anal about greasy kettles. A little here or there is fine, but I prefer to set up a pan or foil to catch anything that is going to drip a lot. An ounce of prevention is worth a pound of cure and I've had greasy bottoms catch on fire - no fun to find your kettle at 600 degrees from fiery gunk.