There have been some developments in the saga...
After posting this thread here (and others on a few other boards), I sent an email to my dealer's service manager, including links to these forum posts. Several days later, I got a phone call from someone at Ducati North America. He said that he'd been forwarded my email by "one of [his] field reps" and he was very sorry for the experience I was having. He said that Ducati was going to extend my factory warranty by 2 years, and that he was working on how to do that for documentation purposes. I thanked him profusely for this, but I also pressed on the issue of the exhaust finish.
They'd previously told me that they didn't want to replace the exhaust because the problem would simply recur, and offered instead to have the bike's exhaust refinished and ceramic coated by a third party shop. I told him that I wasn't really satisfied with this solution, as it would result in a bike that was no longer "stock;" I feel that the whole value of this limited edition motorcycle is in its finish, and my fear is that their solution would decrease the value of the bike in the long term.
I asked him instead to consider replacing the exhaust system with the full Termi system... this would give me a bike that was still "stock," since the Termi system is a factory option, and this upgrade would show good faith on their part towards making things right. He told me that my request was very reasonable, and although he couldn't promise that, he would try to make it happen. I thanked him again for taking the time to call me personally.
A few of weeks later (last week) I got a call from the service manager at my dealership, who told me that they'd located a termi system on a "demo" bike that they were going to remove and ship to my dealership for installation on my bike. He said they'd received all of the titanium bodywork replacement parts, and that the rep said they were working on giving me something in writing regarding the extended warranty.
So... if they do indeed deliver on what they've promised me, I will be completely satisfied and my Ducati fanboy status restored 100 percent. I will post more updates as things occur, but this doesn't seem to be a quick process. I'm okay with that, as long as the end result is Ducati being true to their word.