When cost becomes less a factor, there are lots of good products based on technologies having a domed diaphragm driving a compression horn. Your suggestion may also be a good medium-cost alternative.I'm not sure I'd be happy with response limited to 16kHz in a tweeter of this class though. I used to use a device that generated good response out to 40kHz and I loved the way they sounded. Then again, I quickly stopped using them because they were too fragile and easily blown.
Another direction I'd look at would be the ribbon devices. The old Infinity EMIT tweeters were really something, and now days there are several manufacturers that provide robust high-efficiency models.