If you want something like this, and need a "I just want it to work, require no central coordination, and to have vanishingly small probability of collision" th

If you want something like this, and need a "I just want it to work, require no central coordination, and to have vanishingly small probability of collision" then just use the same concepts but wider than the 128 bit footprint limit of this scheme. This limit makes sense for the RFC in the post, as there backwards compatibility is an explicit goal. But if you used say a 64 bit nanosecond counter (to preserve best case precision on a single machine) along with 128+ bits of random data and you'll need to worry more about gamma ray bursts than collisions.