Probably because my implementation was suspect, but still. Big calculation.
ChIkEn's computer ran the calculation, the best computer in my house only had a gig of ram.
They consist of 640 keys, of which every combination of 3 keys has a unique XOR. As well, every combination of 2 keys also has a unique XOR. Essentially what this means is that if you take Elements A, B, C and xor them, they will never equal Elements D, E, F xor'd. (unless the keys in A B C are the exact same as in D E F).
The numbers (in the form of a C++ array):http://willhostforfood.com/users/C/ChIkEn/results.txt
One of the 11 arrays is completely blank, because its just there for spacing reasons.
Now, practical reasons for this? I thought they'd be good for Zobrist hashing (which forms hashes based on xor combinations of preset keys).
Ensuring every xor combination of 4 elements is unique is probably possible, but would take about 320 times as much RAM, and thousand-folds more running time.