it's not that complicated...
pixelnet, and DMX are NOT Ethernet, they don't use ethernet cables, they don't use networking switches...
they use RJ45 connected cables...
Ethernet requires each data pair to be on a physical pair to get the speed out of the cable...
the RJ45 connector...
1&2 uni1
3&4 uni2
5&6 uni3
7&8 uni4
you can make your cables any way you want as long at the ends match.
Ethernet is high speed and is limited to 328ft (~ a couple feet) <--- has NOTHING to do with pixelnet / DMX so don't try to place ethernet requirements onto something that isn't Ethernet
RJ mentioned that the pixelnet, and or DMX data can travel at least 1000ft. (pixelnet in this case is the connection dongle to hub, or hub to hub, not from hub to ssc)
EDIT: i made an exception for hub to ssc, b/c the distance would most like create a voltage drop, where at least a full string would not light up
old slow ethernet cables work with dmx / pixelnet, (you know the ones where the orange or green pair isn't split)
so, don't worry about the cable except that the pins match (don't use a crossover) and worry about the RJ45 connector physical pins odd,even