I might provide a rough template here if you want to look at code.
Feature Line Split I realize this thread is old, so I am sure you might have solved the problem.
A great Arcpy Cafe post is here those for those who find this post. Split into equal length features | ArcPy Café
PS: If you have lines that do not overlap, the method suggested by ESRI staff is the best way to do this without scripting. In the case of overlapping lines (network analyst routes), the script I have creates a descent template. I have used this script to help with animations (by segmenting routes into smaller portions).
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