One could buy the connectors and flat wire as parts and build a new cable oneself.
You'd have to be very careful to get everything straight and properly pressed. As I have access to a proper crimper at work, I made a new wire for my MkI as I upgraded to two drives (the MkI uses 2 wires, each with a connector at each end, as it has 2 IDE headers on the mainboard) about 2.5 years ago.
It is certainly doable, but I wouldn't try it without the proper crimping tool...
Edit: unless, as Tony points out, it's just a fixable bad crimp on the original wire. I've fixed one of those in a small bench vise.
/Michael
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/Michael