Heh. There are many examples in the outside world of shorter-length hashes that are sorted by various agreements. I think of MIDI sysex headers, for instance, which after specifying that the first hex group would be the manufacturer's ID, the MIDI consortium (of manufacturers of musical instruments) got together and decided that Roland would be 01, Yamaha 0b, and so forth. Unfortunately this formatting restricts any one manufacturer to having less than 256 different keyboards, drum machines, or sound modules that can have a unique ID (as they were given the next hex group for this). In any case. I can easily image a system by which, say, the first two digits uniquely identified the coordinating group or market used by a merchant, the next four digits were their unique ID within that group, and so forth. What I can't imagine is such a system being imposed, or remaining practical after merchants had changed names, stores, partnerships, made mistakes and corrected them, had religious objections to certain number sets, etc.